CHEMISTRY

Atomic Structure

Phasor Academy Contact- 9137061453/7710882858

 Atomic Structure
Index : Preparing your own list of Important/Difficult Questions
Instruction to fill

(A) Write down the Question Number you are unable to solve in column A below, by Pen.
(B) After discussing the Questions written in column A with faculties, strike off them in the
manner so that you can see at the time of Revision also, to solve these questions again.
(C) Write down the Question Number you feel are important or good in the column B.

COLUMN :A COLUMN :B
EXERCISE
NO. Questions I am unable
Good/Important questions
to solve in first attempt

1.

2.

3.
Advantages
1. It is advised to the students that they should prepare a question bank for the revision as it is
very difficult to solve all the questions at the time of revision.

2. Using above index you can prepare and maintain the questions for your revision.

Contents
Topic Page No.
Exercise - 1 01– 08
Exercise - 2 08 – 11

Exercise - 3 11 – 21
Part - I : JEE (Main) /AIEEE Questions

Part - II : JEE (Adv.)/ IIT-JEE Questions

Part - III : NEET / AIPMT Questions (Previous

Year)

Answer Answers 22

SYLLABUS
Atomic Structure : Thomson and Rutherford atomic models and their limitations; Nature of
electromagnetic radiation, photoelectric effect; Spectrum of hydrogen atom, Bohr model of hydrogen atom.
its postulates, derivation of the relations for energy of the electron and radii of the different orbits, limitations
of Bohr.s model; Dual nature of matter, de-Broglie.s relationship, Heisenberg uncertainty principle.
Atomic Structure

 Marked Questions may have for Revision Questions.

OBJECTIVE QUESTIONS
Section (A) : Calculation related to nucleus
A-1. Atomic radius is of the order of 10–8 cm and nuclear radius is of the order of 10–13 cm. Calculate what
fraction of atom is occupied by nucleus?
(1) 10–20 (2) 10–15 (3) 10–12 (4) None

A-2. Atomic weight of an element is not necessarily whole number because

(1) it contains electrons, protons and neutrons (2) it contains allotropic forms
(3) atoms are no longer considered indivisible (4) it contains isotopes

A-3. The charge on the atom having 17 protons, 18 neutrons and 18 electrons is
(1) + 1 (2) – 1 (3) – 2 (4) zero

A-4. Which of the following are isoelectronic with one another ?

(1) Na+ and Ne (2) K+ and O (3) Ne and O (4) Na+ and K+

A-5. Millikan's oil drop expriments is used to find -

(1) e/m ratio of an electron (2) Charge on an electron
(3) Mass of an electron (4) Velocity of an electron
A-6. Which of the following is isoelectronic with N2O :
(1) NO (2) N2O5 (3) CO2 (4) CO

A-7. The e/m is not constant for :

(1) Cathode rays (2) Positive rays (3) α-rays (4) β-rays

A-8. Which one of the following pairs represents isobars -

(1) 2He3 and 2He4 (2) 12Mg24 and 12Mg25
(3) 19K40 and 19K39 (4) 19K40 and 18Ar40

A-9. Cathode rays are made up of

(1) Positively charged particles (2) Negatively charged particles
(3) Neutral particles (4) None of these

A-10. Cathode rays have

(1) Mass only (2) Charge only
(3) No mass and charge (4) Mass and charge both

A-11. Which one of the following pairs is not correctly matched

(1) Rutherford-Proton (2) J.J. Thomsom-Electron
(3) J.H. Chadwick-Neutron (4) Bohr-Isotope

A-12. The nature of anode rays depends upon

(1) Nature of electrode (2) Nature of gas
(3) Nature of discharge tube (4) All the above

A-13. The ratio of the "e/m" (specific charge) values of a electron and an α-particle is -
(1) 2 : 1 (2) 1 : 1 (3) 1 : 2 (4) None of these

PHASOR ACADEMY Mob No: 9137061453 Page 1

Atomic Structure
A-14. The positive charge of an atom is
(1) Spread all over the atom (2) Distributed around the nucleus
(3) Concentrated at the nucleus (4) All of these

A-15. The mass of an atom is constituted mainly by

(1) Neutron and neutrino (2) Neutron and electron
(3) Neutron and proton (4) Proton and electron

A-16. Neutrons are found in atoms of all elements except in

(1) Chlorine (2) Oxygen (3) Argon (4) Hydrogen

A-17. Six protons are found in the nucleus of

(1) Boron (2) Lithium (3) Carbon (4) Helium

A-18.When atoms are bombarded with alpha particles, only a few in million suffer deflection, others pass out
undeflected. This is because
(1) The force of repulsion on the moving alpha particle is small
(2) The force of attraction on the alpha particle to the oppositely charged electrons is very small
(3) There is only one nucleus and large number of electrons
(4) The nucleus occupies much smaller volume compared to the volume of the atom

Section (B) : Quantum theory of light and photoelectric Effect

B-1. AIR service on Vividh Bharati is transmitted on 219 m band. What is its transmission frequency in
Hertz?
(1) 1.3 × 106 Hz (2) 1.9 × 106 Hz (3) 1 × 106 Hz (4) 6.5 × 106 Hz

B-2. If 10–17J of light energy is needed by the interior of human eye to see an object. The number of
photons of green light (λ = 550 nm) needed to see the object are :
(1) 27 (2) 28 (3) 29 (4) 30

B-3. Which of the following statements is false :

(1) The energy of red photon is more than the energy of violet photon
(2) The momentum of photon is inversely proportional to its wave length
(3) The energy of a photon is inversely proportional to its wave length
(4) The particle nature of electromagnetic radiations is able to explain the photoelectric effect

B-4. Light of wavelength λ falls on metal having work function hc/λ0. Photoelectric effect will take place only
if :
(1) λ > λ0 (2) λ > 2λ0 (3) λ < λ0 (4) λ < λ0/2

B-5. A photon in X region is more energetic than in the visible region ; X is :

(1) IR (2) UV (3) Microwave (4) Radio wave

B-6. A bulb of 40 W is producing a light of wavelength 620 nm with 80% of efficiency then the number of
photons emitted by the bulb in 20 seconds are (1eV = 1.6 × 10–19 J, hc = 12400 eV Å)
(1) 2 × 1018 (2) 1018 (3) 1021 (4) 2 × 1021

B-7. Which one of the following is not the characteristic of Planck's quantum theory of radiation-
(1) The energy is not absorbed or emitted in whole number multiple of quantum.
(2) Radiation is associated with energy.
(3) Radiation energy is not emitted or absorbed continously but in the form of small packets called
quanta.
(4) This magnitude of energy associated with a quantum is proportional to the frequency.

PHASOR ACADEMY Mob No: 9137061453 Page 2

Atomic Structure
B-8. Calculate the frequency of a photon of wavelength 4000 Å
(1) 7.5 × 1014 s–1 (2) 7.5 × 10–16 s–1 (3) 8 × 10–14 s–1 (4) 6.5 × 10–15 s–1

B-9. Calculate the wavelength of a photon having an energy of 2 electron volt

(1) 6.204 × 10–7 m (2) 6.206 × 10–6 m (3) 6.204 × 10–9 m (4) 6.204 × 10–8 m

B-10. Photoelectric effect is maximum in :

(1) Cs (2) Na (3) K (4) Li

B-11. The MRI (magentic resonance imaging) body scanners used in hospitals operate with 400 MHz radio
frequency. The wavelength corresponding to this radio frequency is
(1) 0.75 m (2) 0.75 cm (3) 1.5 m (4) 2 cm

B-12. Photon of which light has maximum energy :

(1) red (2) blue (3) violet (4) green

Section (C) : Bohr Model

C-1. The ionization energy of He+ is 19.6 × 10–18 J atom–1. The energy of the first stationary state of Li+2 will
be:
(1) 84.2 × 10–18 J/atom (2) 44.10 × 10–18 J/atom
(3) 63.2 × 10 J/atom
–18 (4) 21.2 × 10–18 J/atom

C-2. Energy required to pull out an electron from 1st orbit of hydrogen atom to infinity is 100 units. The
amount of energy needed to pull out the electron from 2nd orbit to infinity is :
(1) 50 units (2) 100 units (3) 25 units (4) Zero

C-3. The ionization energy of H-atom is 13.6 eV. The ionization energy of Li+2 ion will be :
(1) 54.4 eV (2) 122.4 eV (3) 13.6 eV (4) 27.2 eV

C-4. Which of the following electron transition in a hydrogen atom will require the largest amount of energy ?
(1) From n = 1 to n = 2 (2) From n = 2 to n = 3 (3) From n = ∞ to n = 1 (4) From n = 3 to n = 5

C-5. What is likely to be orbit number for a circular orbit of diameter 20 nm of the hydrogen atom if we
assume Bohr orbit to be the same as that represented by the principal quantum number?
(1) 10 (2) 14 (3) 12 (4) 16

C-6. If velocity of an electron in Ι orbit of H atom is V, what will be the velocity of electron in 3rd orbit of Li+2
(1) V (2) V/3 (3) 3 V (4) 9 V

C-7. Match the following

(A) Energy of ground state of He+ (i) + 6.04 eV
(B) Potential energy of Ι orbit of H-atom (ii) –27.2 eV
(C) Kinetic energy of ΙΙ excited state of He+ (iii) 54.4 V
(D) Ionisation potential of He+ (iv) – 54.4 eV
(1) A – (i), B – (ii), C – (iii), D – (iv) (2) A – (iv), B – (iii), C – (ii), D – (i)
(3) A – (iv), B – (ii), C – (i), D – (iii) (4) A – (ii), B – (iii), C – (i), D – (iv)

C-8. S1 : Bohr model is applicable for Be2+ ion.

S2 : Total energy coming out of any light source is integral multiple of energy of one photon.
S3 : Number of waves present in unit length is wave number.
S4 : e/m ratio in cathode ray experiment is independent of the nature of the gas.
(1) F F T T (2) T T F F (3) F T T T (4) T F F F

PHASOR ACADEMY Mob No: 9137061453 Page 3

Atomic Structure
C-9. S1 : Potential energy of the two opposite charge system increases with the decrease in distance.
S2 : When an electron make transition from higher orbit to lower orbit it's kinetic energy increases.
S3 : When an electron make transtition from lower energy to higher energy state its potential energy
increases.
S4 : 11eV photon can free an electron from the 1st excited state of He+ -ion.
(1) T T T T (2) F T T F (3) T F F T (4) F F F F

C-10. If r1 is the radius of the first orbit of hydrogen atom, then the radii of second, third and fourth orbits in
terms of r1 are :
(1) r12, r13, r14 (2) 8r1, 27r1, 64r1 (3) 4r1, 9r1 16r1 (4) 2r1, 6r1, 8r1

C-11. Bohr's model can explain :

(1) The spectrum of hydrogen atom only
(2) The spectrum of atom or ion containing one electron only
(3) The spectrum of hydrogen molecule only
(4) The solar spectrum

C-12. If electron falls from n= 3 to n = 2, then emitted energy is :

(1) 10.2 eV (2) 12.09 eV (3) 1.9 eV (4) 0.65 eV
C-13. The maximum energy is present in any electron at
(1) Nucleus (2) Ground state
(3) First excited state (4) Infinite distance from the nucleus

Section (D) : Spectrum

D-1. If the series limit of wavelength of the Lyman series for the hydrogen atoms is 912Å, then the series
limit of wavelength for the Balmer series of the hydrogen atom is :
(1) 912 Å (2) 912 × 2 Å (3) 912 × 4 Å (4) 912/2 Å

D-2. The shortest wave length in H spectrum of Lymen series when RH = 109678 cm–1 is
(1) 1002.7 Å (2) 1215.67 Å (3) 1127.30 Å (4) 911.7 Å

D-3. According to Bohr’s theory, the angular momentum for an electron in 5th orbit is :
(1) 2.5 h/π (2) 5 h/π (3) 25 h/π (4) 5π /2h

D-4. Transition of an electron from n = 3 to n = 1 level results in

(1) emission spectrum (2) band spectrum (3) infrared spectrum (4) X-ray spectrum

D-5. If r is the radius of first orbit, the radius of nth orbit of H atom is given by -
(1) r n (2) r n2 (3) r/n (4) r2 n2

D-6. The radius of hydrogen in ground state is 0.53 Å. In normal state the radius of Li2+ (atomic number = 3)
in ground state will be :
(1) 1.06 Å (2) 0.265 Å (3) 0.17 Å (4) 0.53 Å

D-7. The minimum energy required to excite a hydrogen atom from its ground state is -
(1) 3.4 eV (2) 13.6 eV (3) – 13.6 eV (4) 10.2 eV

D-8. The separation energy of the electron present in the shell n = 3 is 1.51 eV. What is the energy in the
first excited state –
(1) –1.51 eV (2) –3.4 eV (3) +1.51 eV (4) +3.4 eV

PHASOR ACADEMY Mob No: 9137061453 Page 4

Atomic Structure
D-9. The wavelength of a spectral line for an electronic transition is inversely related to :
(1) number of electrons undergoing transition
(2) the nuclear charge of the atom
(3) the velocity of an electron undergoing transition
(4) the difference in the energy levels involved in the transition

D-10. In a sample of H-atom electrons make transition from 5th excited state to ground state, producing all
possible types of photons, then number of lines in infrared region are
(1) 4 (2) 5 (3) 6 (4) 3

D-11. Calculate wavelength of 3rd line of Bracket series in hydrogen spectrum

784 33R 784R 33
(1) (2) (3) (4)
33R 784 33 784R

D-12. In Balmer series of hydrogen atom spectrum which electronic transition causes third line
(1) Fifth Bohr orbit to second one (2) Fifth Bohr orbit to first one
(3) Fourth Bohr orbit to second one (4) Fourth Bohr orbit to first one

D-13 . The emission spectrum of hydrogen is found to satisfy the expression for the energy change. ∆E (in
 1 1 
joules) such that ∆E= 2.18 × 10  2 − 2  J where n1 = 1, 2, 3….. and n2 = 2, 3, 4……. The spectral
n
 1 n2 
lines correspond to Paschen series to
(1) n1 = 1 and n2 = 2, 3, 4 (2) n1 = 3 and n2 = 4, 5, 6
(3) n1 = 1 and n2 = 3, 4, 5 (4) n1 = 2 and n2 = 3, 3, 5

D-14. Calculate the wavelength of 1st line of Balmer series in Hydrogen spectrum.
(1) 6656 Å (2) 6266 Å (3) 6626 Å (4) 6566 Å

D-15. Different lines in Lyman series of hydrogen spectrum lie in

(1) ultraviolet (2) infrared (3) visible (4) none of these

D-16. The transition of the electron in hydrogen atom from the fourth to first energy shell emits a spectral line
which falls in following series.
(1) Lyman (2) Balmer (3) Pashen (4) Bracket

D-17. When an electron in an excited hydrogen atom jumps from an energy level for which n = 5 to a lower
level for which n = 2 , the spectral line is observed in the ..........region and in .............series of the
hydrogen spectrum.
(1) Visible, Balmer (2) Visible, lyman (3) Infrared, lyman (4) Infrared, Balmer

D-18. Which of the following transition is correct for Balmer series ?

(1) 3 → 1 (2) 1 → 2 (3) 4 → 2 (4) 2 → 4

Section (E) : De broglie wavelength & Uncertainity principle

E-1. What possibly can be the ratio of the de Broglie wavelengths for two electrons each having zero initial
energy and accelerated through 50 volts and 200 volts ?
(1) 3 : 10 (2) 10 : 3 (3) 1 : 2 (4) 2 : 1
E-2. The speed of a proton is one hundredth of the speed of light in vacuum. What is its de-Broglie
wavelength? Assume that one mole of protons has a mass equal to one gram.
[h = 6.626 × 10–27 erg sec] :
(1) 13.31 × 10–7 Å (2) 1.33 × 10–3 Å (3) 13.13 × 10–5 Å (4) 1.31 × 10–2 Å

PHASOR ACADEMY Mob No: 9137061453 Page 5

Atomic Structure
E-3. An α-particle is accelerated through a potential difference of V volts from rest. The de-Broglie’s
wavelength associated with it is
150 0.286 0.101 0.983
(1) Å (2) Å (3) Å (4) Å
V V V V

E-4. The uncertainity in position and velocity of a particle are 10–10 m and 5.27 × 10–24 ms–1 respectively.
Calculate the mass of the particle (h = 6.625 × 10–34 Joule sec.)
(1) 0.099 Kg (2) 0.089 Kg (3) 0.99 Kg (4) Can not predict

E-5. It the uncertainity in position of a moving particle is 0 then find out ∆P

(1) 0 (2) 1 (3) ∞ (4) Can not predict

E-6. The de Broglie equation suggests that an electron has

(1) Particle nature (2) Wave nature
(3) Particle-wave nature (4) Radiation behaviour

E-7. The Uncertainity in the momentum of an electron is 1.0 × 10–5 kg m s–1 . The Uncertainity in its position
will be: (h = 6.626 × 10–34 Js)
(1) 1.05 × 10–28 m (2) 1.05 × 10–26 m (3) 5.27 × 10–30 m (4) 5.25 × 10–28 m

E-8. Which of the following has least de Broglie λ

(1) e– (2) p (3) CO2 (4) SO2

E-9. A helium molecule is moving with a velocity of 2.40 x 102 ms–1 at 300k. The de-Broglie wave length is
about
(1) 0.416 nm (2) 0.83 nm (3) 803 Å (4) 8000 Å

E-10. In H-atom, if ‘x’ is the radius of the first Bohr orbit, de Broglie wavelength of an electron in 3rd orbit is :
9x x
(1) 3 π x (2) 6 π x (3) (4)
2 2

E-11. The wavelength of a charged particle ________the square root of the potential difference through which
it is accelerated :
(1) is inversely proportional to (2) is directly proportional to
(3) is independent of (4) is unrelated with

E-12. A ball weight 25 g moves with a velocity of 6.6 × 104 cm/sec then find out the de Broglie wavelength.
(1) 0.4 × 10–33 cm (2) 0.4 × 10–31 cm (3) 0.4 × 10–30 cm (4) 0.4 × 1020 cm

E-13. Calculate the uncertainity in velocity of a cricket ball of mass 150 g if the uncertainity in its position is of
the order of 1 Å (h = 6.6 × 10–34 Kg m2 s–1 )
(1) 3.499 × 10–24 ms–1 (2) 3.499 × 10–21 ms–1 (3) 3.499 × 10–20 ms–1 (4) 3.499 × 10–30 ms–1

E-14. The de-Broglie equation applies

(1) To electrons only (2) To neutrons only
(3) To protons only (4) All the material object in motion

E-15. The uncertainty in momentum of an electron is 1 × 10–5 kg-m/s. The uncertainty in its position will be :
(h = 6.62 × 10–34 kg-m2/s)
(1) 1.05 × 10–28 m (2) 1.05 × 10–26 m (3) 5.27 × 10–30 m (4) 5.27 × 10–28 m

PHASOR ACADEMY Mob No: 9137061453 Page 6

Atomic Structure
Section (F) : Quantum numbers & Electronic configuration
F-1. The orbital angular momentum of an electron in 2s-orbital is -
h h 2 h
(1) (2) zero (3) (4)
4π 2π 2π

F-2. Which of the following set of quantum numbers are permitted

(1) n = 3, l = 2, m = – 2, s = +1/2 (2) n = 3, l = 2, m = – 1, s = 0
(3) n = 2, l = 2, m = +1, s = – 1/2 (4) n = 2, l = 2, m = +1, s = – 1/2

F-3. A given orbital is labeled by the magnetic quantum number m = –1. This could not be
(1) s - orbital (2) p-orbital (3) d-orbital (4) f-orbital

F-4. Magnetic quantum number specifies -

(1) Size of orbitals (2) Shape of orbitals
(3) Orientation of orbitals (4) Nuclear stability

F-5. For the energy levels in an atom which one of the following statements is correct :
(1) The 4s sub-energy level is at a higher energy than the 3d sub-energy level
(2) The second principal energy level can have five orbitals and contain a maximum of 10 electrons
(3) The M-energy level can have maximum of 32 electrons
(4) None of these

F-6. Which of the following represents the correct set of quantum numbers of a 4d electron ?
1 1 1
(1) 4, 3, 2, + (2) 4, 2, 1, 0 (3) 4, 3, – 2, + (4) 4, 2, 1, –
2 2 2

F-7. A p-orbital can accommodate

(1) 4 electrons (2) 6 electrons
(3) 2 electrons with parallel spins (4) 2 electrons with opposite spins

1
F-8. An orbital containing electron having quantum number n = 4, l = 3, m = 0 and s = – is called
2
(1) 3s orbital (2) 3p orbital (3) 4d orbital (4) 4f orbital

F-9. The maximum number of electrons in a subshell is given by the expression

(1) 4 – 2 (2) 4 + 2 (3) 2 + 2 (4) 2n2

F-10. The electrons present in K-shell of the atom will differ in

(1) principal quantum number (2) azimuthal quantum number
(3) magnetic quantum number (4) spin quantum number
F-11. Magnetic moment of Xn+ (Z = 26) is 24 B.M. Hence number of unpaired electrons and value of n
respectively are :
(1) 4, 2 (2) 2, 4 (3) 3, 1 (4) 0, 2

F-12. For an electron, with n = 3 has only one radial node. The orbital angular momentum of the electron will
be
h 2 h  h 
(1) 0 (2) 6 (3) (4) 3  
2π 2π  2π 

F-13. The maximum number of 3d-electrons having spin quantum number s = +1/2 are -
(1) 10 (2) 14 (3) 5 (4) None of these

PHASOR ACADEMY Mob No: 9137061453 Page 7

Atomic Structure
F-14. In which (n + ) rules not applicable -
(1) Cu, Cr (2) Cu, Zn (3) Ag, Zn (4) All of these

F-15. The quantum numbers for the outermost electron of an element are given below as n = 2, l = 0, m = 0,
1
s=+ . The atoms is :
2
(1) Lithium (2) Beryllium (3) Hydrogen (4) Boron

F-16.An element has the electronic configuration 1s2, 2s2 2p6, 3s2 3p2. Its valency electrons are :
(1) 6 (2) 2 (3) 3 (4) 4

F-17. The number of orbitals in 2p sub-shell is :

(1) 6 (2) 2 (3) 3 (4) 4

F-18. Which of the following has the least energy :

(1) 2p (2) 3p (3) 2s (4) 4d

F-19. Which of the following principles/rules limits the maximum number of electrons in an orbital to two
(1) Aufbau principle (2) Pauli's exclusion principle
(3) Hund's rule of maximum multiplicity (4) Heisenberg's uncertainty principle

 Marked Questions may have for Revision Questions.

PART - I : OBJECTIVE QUESTIONS

1. For  = 1, n = 3 the corresponding orbitals are -
(1) s, px , py (2) s, pz , py (3) s , px , dxy (4) px , py, pz

2. A sodium cation has different number of electrons from :

(1) O2– (2) F– (3) Li+ (4) Al3+

3. Number of electrons in –CONH2 is :

(1) 22 (2) 24 (3) 20 (4) 28

4. If the atomic weight of an element is 23 times that of the lightest element and it has 11 protons, then it
contains :
(1) 11 protons, 23 neutrons, 11 electrons (2) 11 protons, 11 neutrons, 11 electrons
(3) 11 protons, 12 neutrons, 11 electrons (4) 11 protons, 11 neutrons, 23 electrons

5. A photon of 300 nm is absorbed by a gas and then emits two photons. One photon has a wavelength
496 nm then the wavelength of second photon in nm :
(1) 759 (2) 859 (3) 959 (4) 659

6. If the energy of an electron in hydrogen atom is given by expression, –1312/n² kJ mol–1, then the
energy required to excite the electron from ground state to second orbit is
(1) 328 kJ/mol (2) 656 kJ/mol (3) 984 kJ/mol (4) 1312 kJ/mol

7. The ionization energy of H atom is 13.6 eV what will be ionization energy of He+ and Li+2 ions-
(1) - 54.4 ev and - 12.2 ev (2) 122.4 ev and 55.4 ev
(3) 54.4 ev and 122.4 ev (4) 12.1 ev and 13.6 ev

PHASOR ACADEMY Mob No: 9137061453 Page 8

Atomic Structure
8. The frequency corresponding to transition n = 2 to n = 1 in hydrogen atom is :
(1) 15.66 × 1010 Hz (2) 24.66 × 1014 Hz (3) 30.57 × 1014 Hz (4) 40.57 × 1024 Hz

9. The difference between the wave number of 1st line of Balmer series and last line of paschen series for
Li2+ ion is :
R 5R R
(1) (2) (3) 4R (4)
36 36 4

10. The wave number of electromagnetic radiation emitted during the transition of electron in between two
levels of Li2+ ion whose principal quantum numbers sum is 4 and difference is 2 is :
8
(1) 3.5 RH (2) 4 RH (3) 8 RH (4) RH
9

11. No. of visible lines when an electron returns from 5th orbit to ground state in H spectrum -
(1) 5 (2) 4 (3) 3 (4) 10

12. If the shortest wave length of Lyman series of H atom is x, then the wave length of the first line of
Balmer series of H atom will be -
(1) 9x/5 (2) 36x/5 (3) 5x/9 (4) 5x/36

13. Suppose that a hypothetical atom gives a red, green, blue and violet line spectrum. Which jump
according to figure would give off the red spectral line.

(1) 3 → 1 (2) 2 → 1 (3) 4 → 1 (4) 3 → 2

14. If wavelength is equal to the distance travelled by the electron in one second, then -
h h h h
(1) λ = (2) λ = (3) λ = (4) λ =
p m p m

15. de-Broglie wavelength of electron in second orbit of Li2+ ion will be equal to de-Broglie of wavelength of
electron in
(1) n = 3 of H-atom (2) n = 4 of C5+ ion (3) n = 6 of Be3+ ion (4) n = 3 of He+ ion

16. De Broglie wavelength of an electron after being accelerated by a potential difference of V volt from rest
is
12.3 12.3 12.3 12.3
(1) λ = Å (2) λ = Å (3) λ = Å (4) λ = Å
h V E m

17. What is the de-Broglie wavelength associated with the hydrogen electron in its third orbit :
(1) 9.96 × 10–10 cm (2) 9.96 × 10–8 cm (3) 9.96 × 104 cm (4) 9.96 × 108 cm

18. Uncertainity in position is twice the Uncertainity in momentum. Uncertainity in velocity is :

h 1 h 1 h
(1) (2) (3)  (4)
π 2m π 2m 4π

19. Which orbital is non-directional :

(1) s (2) p (3) d (4) All

PHASOR ACADEMY Mob No: 9137061453 Page 9

Atomic Structure
20. If n and  are respectively the principal and azimuthal quantum numbers, then the expression for
calculating the total number of electrons in any orbit is -
=n = n − 1 = n + 1 = n − 1
(1) ∑
 =1
2(2 + 1) (2) ∑
 =1
2(2 + 1) (3) ∑
=0
2(2 + 1) (4) ∑
=0
2(2 + 1)

21. After np orbitals are filled, the next orbital filled will be :
(1) (n + 1) s (2) (n + 2) p (3) (n + 1) d (4) (n + 2) s

22. Which of the above statement (s) is/are false.

I. Orbital angular momentum of the electron having n = 5 and having value of the azimuthal quantum
h
number as lowest for this principle quantum number is .
π
II. If n = 3,  = 0, m = 0, for the last valence shell electron, then the possible atomic number may be 12
or 13.
7
III. Total spin of electrons for the atom 25Mn is ± .
2
IV. Spin magnetic moment of inert gas is 0

(1) I, II and III (2) II and III only (3) I and IV only (4) None of these

23. In case of dx2 − y2 orbital

(1) Probability of finding the electron along x-axis is zero.

(2) Probability of finding the electron along y-axis is zero.
(3) Probability of finding the electron is maximum along x and y-axis.
(4) Probability of finding the electron is zero in x-y plane

24. Match List-I with List-II and select the correct answer using the codes given below the lists ( and m are
respectively the azimuthal and magnetic quantum no.)
List-I List-II
(A) Number of value of  for an energy level (1) 0, 1, 2, ............. (n - 1)
(B) Value of  for a particular type of orbital (2) + to – through zero
(C) Number of values of m for  = 2 (3) 5
(D) Value of 'm' for a particular type of orbital (4) n

Code :
A B C D A B C D
(1) 4 1 2 3 (2) 4 1 3 2
(3) 1 4 2 3 (4) 1 4 3 2

25. Nitrogen has the electronic configuration 1s2,2s22px12py12pz1 and not 1s2,2s22px22py12pz0 which is
determined by
(1) Aufbau's principle (2) Pauli's exclusion principle
(3) Hund's rule (4) Uncertainty principle

26. For sodium atom the number of electrons with m = 0 will be :

(1) 2 (2) 7 (3) 9 (4) 8

PHASOR ACADEMY Mob No: 9137061453 Page 10

Atomic Structure
27. Assertion : Hydrogen has one electron in its orbit but it produces several spectral lines.
Reason : There are many excited energy levels available.
(1) Both assertion and reason are correct, and the reason is the correct explanation for the assertion
(2) Both assertion and reason are correct, but the reason is not the correct explanation for the assertion
(3) The assertion is incorrect, but the reason is correct
(4) Both are assertion and reason are incorrect
28. Assertion : The energy of an electron is largely determined by its principal quantum number.
Reason : The principal quantum number (n) is a measure of the most probable distance of finding the
electron around the nucleus.
(1) Both assertion and reason are correct, and the reason is the correct explanation for the assertion
(2) Both assertion and reason are correct, but the reason is not the correct explanation for the assertion
(3) The assertion is incorrect, but the reason is correct
(4) Both are assertion and reason are incorrect

PART - I : JEE (MAIN) / AIEEE PROBLEMS (PREVIOUS YEARS)

OFFLINE JEE-MAIN
1. Which of the following ions has the maximum magnetic moment ? [AIEEE 2002, 3/225]
(1) Mn2+ (2) Fe2+ (3) Ti2+ (4) Cr2+

2. Energy of H-atom in the ground state is –13.6 eV, hence energy in the second excited state is :
[AIEEE 2002, 3/225]
(1) – 6.8 eV (2) – 3.4 eV (3) – 1.51 eV (4) – 4.53 eV

3. Uncertainity in position of a particle of 25 g in space is 10–15 m. Hence, Uncertainity in velocity (m.sec–1)

is: (plank’s constant, h = 6.6 × 10–34 Js) [AIEEE 2002, 3/225]
(1) 2.1 × 10–18 (2) 2.1 × 10–34 (3) 0.5 × 10–34 (4) 5.0 × 10–24

4. The de-Broglie wavelength of a tennis ball of mass 60 g moving with a velocity of 10 m/s is
approximately. (planck’s constant, h = 6.63 × 10–34 J-s) [AIEEE 2003, 3/225]
(1) 10–33 m (2) 10–31 m (3) 10–16 m (4) 10–25 m

5. In Bohr series of lines of hydrogen spectrum, the third line from the red end corresponds to which one
of the following inner-orbit jumps of the electron for Bohr orbits in an atom of hydrogen ?
[AIEEE 2003, 3/225]
(1) 3 → 2 (2) 5 → 2 (3) 4 → 1 (4) 2 → 5

6. The numbers of d-electrons retained in Fe2+ (atomic number Fe = 26) ion is [AIEEE 2003, 3/225]
(1) 3 (2) 4 (3) 5 (4) 6

h
7. The orbital angular momentum for an electron revolving in an orbit is given by . This
 ( + 1)
2π
momentum for an s-electron will be given by [AIEEE 2003, 3/225]
1 h h 2. h
(1) + . (2) Zero (3) (4)
2 2π 2π 2π

PHASOR ACADEMY Mob No: 9137061453 Page 11

Atomic Structure
8. Which one of the following groupings represents a collection of isoelectronic species?
(At. nos. : Cs-55, Br-35) [AIEEE 2003, 3/225]
(1) Na , Ca , Mg
+ 2+ 2+ (2) N , F , Na
3– – + (3) Be, Al , Cl
3+ – (4) Ca , Cs+, Br.
2+

9. The wavelength of the radiation emitted, when in a hydrogen atom electron falls from infinity to
stationary state 1, would be (Rydberg constant = 1.097 × 107 m–1) [AIEEE 2004, 3/225]
(1) 91 nm (2) 192 nm (3) 406 (4) 9.1 × 10–6 nm

10. Which of the following set a of quantum numbers is correct for an electron in 4f orbital ?
[AIEEE 2004, 3/225]
(1) n = 4, l = 3, m = +4, s = +1/2 (2) n = 4, l = 4, m = –4, s = –1/2
(3) n = 4, l = 3, m = +1, s = +1/2 (4) n = 3, l=2, m =–2, s = +1/2

11. Consider the ground state of Cr atom (Z = 24). The numbers of electrons with the azimuthal quantum
numbers,  = 1 and 2 are, respectively [AIEEE 2004, 3/225]
(1) 12 and 4 (2) 12 and 5 (3) 16 and 4 (4) 16 and 5

12. Which of the following statements in relation to the hydrogen atom is correct ?
[AIEEE 2005, 4½/225]
(1) 3s, 3p and 3d orbitals all have the same energy
(2) 3s and 3p orbitals are of lower energy than 3d orbital
(3) 3p orbital is lower in energy than 3d orbital
(4) 3s orbital is lower in energy than 3p orbital

13. In a multi-electron atom, which of the following orbitals described by the three quantum numbers will
have the same energy in the absence of magnetic and electric field ? [AIEEE 2005, 3/225]
(i) n = 1, l = 0, m = 0 (ii) n = 2, l = 0, m = 0 (iii) n = 2, l = 1, m = 1 (iv) n = 3, l = 2, m =1
(v) n = 3, l = 2, m = 0
(1) (iv) and (v) (2) (iii) and (iv) (3) (ii) and (iii) (4) (i) and (ii)
14. Uncertainity in the position of an electron (mass = 9.1 × 10–31 Kg) moving with a velocity 300 m.sec–1,
Accurate upto 0.001%, will be : (h = 6.63 × 10–34 J-s) [AIEEE 2006, 3/165]
(1) 19.2 × 10 m –2 (2) 5.76 × 10 m –2 (3) 1.92 × 10 m –2 (4) 3.84 × 10–2 m

15. According to Bohr’s theory, the angular momentum to an electron in 5th orbit is : [AIEEE 2006, 3/165]
h h h h
(1) 25 (2) 1.0 (3) 10 (4) 2.5
π π π π

16. The ‘spin-only’ magnetic moment [in units of Bohr magneton (µβ)] of Ni2+ in aqueous solution would be
(Atomic number : Ni = 28) [AIEEE 2006, 3/165]
(1) 2.84 (2) 4.90 (3) 0 (4) 1.73

17. Which of the following nuclear reactions will generate an isotope ? [AIEEE 2007, 3/120]
(1) Neutron particle emission (2) Positron emission
(3) α-particle emission (4) β-particle emission

18. Which of the following set of quantum numbers represents the highest energy of an atom ?
[AIEEE 2007, 3/105]
1 1
(1) n = 3, l = 0, m = 0, s = + (2) n = 3, l = 1, m =1, s = +
2 2
1 1
(3) n = 3, l = 2, m = 1, s = + (4) n = 4, l = 0, m = 0, s = +
2 2

PHASOR ACADEMY Mob No: 9137061453 Page 12

Atomic Structure
19. The ionisation enthalpy of hydrogen atom is 1.312 × 106 J mol–1. The energy required to excite the
electron in the atom from n1 = 1 to n = 2 is [AIEEE 2008, 3/105]
(1) 8.51 × 105 J mol–1 (2) 6.56 × 105 J mol–1 (3) 7.56 × 105 J mol–1 (4) 9.84 × 105 J mol–1

20. Which one of the following constitutes a group of the isoelectronic species? [AIEEE 2008, 3/105]
(1) NO+, C22–, CN–, N2 (2) CN–, N2, O22–, C22– (3) N2, O2–. NO+, CO (4) C22–, O2–, CO, NO

21. Calculate the wavelength (in nanometer) associated with a proton moving at 1.0 × 103 m s–1 (Mass of
proton = 1.67 × 10–27 kg and h = 6.63 × 10–34 J-s) : [AIEEE 2009, 4/144]
(1) 0.40 nm (2) 2.5 nm (3) 14.0 nm (4) 0.032 nm

22. In an atom, an electron is moving with a speed of 600 m/s with an accuracy of 0.005%. Certainity with
which the position of the electron can be located is (h = 6.6 × 10–34 kg m2 s–1, mass of electron, em = 9.1
× 10–31 kg): [AIEEE 2009, 4/144]
(1) 5.10 × 10–3 m (2) 1.92 × 10–3 m (3) 3.83 × 10–3 m (4) 1.52 × 10–4 m

23. The energy required to break one mole of Cl–Cl bonds in Cl2 is 242 kJ mol–1. The longest wavelength of
light capable of breaking a single Cl–Cl bond is : (c = 3 × 108 m s–1 and NA = 6.02 × 1023 mol–1)
[AIEEE 2010, 8/144]
(1) 594 nm (2) 640 nm (3) 700 nm (4) 494 nm

24. Ionisation energy of He+ is 19.6 × 10–18 J atom–1. The energy of the first stationary state (n = 1) of Li2+ is
: [AIEEE 2010, 8/144]
(1) 4.41 × 10 J atom
–16 –1 (2) – 4.41 × 10 J atom
–17 –1

(3) – 2.2 × 10–15 J atom–1 (4) 8.82 × 10–17 J atom–1

25. A gas absorbs a photon of 355 nm and emits at two wavelengths. If one of the emission is at 680 nm,
the other is at : [AIEEE 2011, 4/120]
(1) 1035 nm (2) 325 nm (3) 743 nm (4) 518 nm

26. The frequency of light emitted for the transition n = 4 to n = 2 of He+ isequalto the transition in H atom
corresponding to which of the following? [AIEEE 2011, 4/120]
(1) n = 2 to n = 1 (2) n = 3 to n = 2 (3) n = 4 to n = 3 (4) n = 3 to n = 1

27. The electrons identified by quantum numbers n and  : [AIEEE 2012, 4/120]
(a) n = 4,  = 1 (b) n = 4,  = 0 (c) n = 3,  = 2 (d) n = 3,  = 1
can be placed in order of increasing energy as :
(1) (c) < (d) < (b) < (a) (2) (d) < (b) < (c) < (a) (3) (b) < (d) < (a) < (c) (4) (a) < (c) < (b) < (d)

 Z2 
28. Energy of an electron is given by E = –2.178 × 10–18J   . Wavelength of light required to excite an
 n2 
electron in an hydrogen atom from level n = 1 to n = 2 will be : [JEE(Main)2013, 4/120]
(h = 6.62 × 10–34 Js and c = 3.0 × 108 ms–1)
(1) 1.214 × 10–7 m (2) 2.816 × 10–7 m (3) 6.500 × 10–7 m (4) 8.500 × 10–7 m

29. The correct set of four quantum numbers for the valence electrons of rubidium atom (Z = 37) is :
[JEE(Main)2014, 4/120]
1 1 1 1
(1) 5, 0, 0, + (2) 5, 1, 0, + (3) 5,1, 1, + (4) 5, 0, 1, +
2 2 2 2

PHASOR ACADEMY Mob No: 9137061453 Page 13

Atomic Structure
30. Which of the following is the energy of a possible excited state of hydrogen ? [JEE(Main) 2015, 4/120]
(1) +13.6 eV (2) –6.8 eV (3) –3.4 eV (4) +6.8 eV

31. A stream of electrons from a heated filament was passed between two charged plates kept at a
potential difference V esu. If e and m are charge and mass of an electron, respectively, then the value
of h/λ (where λ is wavelength associated with electron wave) is given by : [JEE(Main) 2016, 4/120]
(1) 2meV (2) meV (3) 2meV (4) meV

32. The radius of the second Bohr orbit for hydrogen atom is :
(Planck's Const. h = 6.6262 × 10–34 Js; mass of electron = 9.1091 × 10–31 kg; charge of electron
e = 1.60210 × 10–19 C; permittivity of vacuum ∈0 = 8.854185 × 10–12 kg–1m–3A2)
[JEE(Main) 2017, 4/120]
(1) 4.76 Å (2) 0.529 Å (3) 2.12 Å (4) 1.65 Å

ONLINE JEE-MAIN
1. The energy of an electron in first Bohr orbit of H-atom is –13.6 eV. The energy value of electron in the
excited state of Li2+ is : [JEE(Main) 2014 Online (09-04-14), 4/120]
(1) – 27.2 eV (2) 30.6 eV (3) – 30.6 eV (4) 27.2 eV

2. If λ0 and λ be the threshold wavelength and wavelength of incident light, the velocity of photoelectron
ejected from the metal surface is : [JEE(Main) 2014 Online (11-04-14), 4/120]
2h 2hc 2hc  λ 0 − λ  2h  1 1 
(1) (λ0 − λ ) (2) (λ0 − λ ) (3) (4) −
m m m  λλ 0  m  λ 0 λ 

 1 1
3. Based on the equation : ∆E = 2.0 × 10–18 J  2 – 2 
 n2 n1 
the wavelength of the light that must be absorbed to excite hydrogen electron from level n = 1 to level n
= 2 will be : (h = 6.625 × 10–34 Js, C = 3 × 108 ms–1) [JEE(Main) 2014 Online (09-04-14), 4/120]
(1) 1.325 × 10–7 m (2) 1.325 × 10–10 m (3) 2.650 × 10–7 m (4) 5.300 × 10–10 m

4. If m and e are the mass and charge of the revolving electron in the orbit of radius r for hydrogen atom,
the total energy of the revolving electron will be : [JEE(Main) 2014 Online (12-04-14), 4/120]
1 e2 e2 me2 1 e2
(1) (2) – (3) (4) –
2 r r r 2 r
5. The de-Broglie wavelength of a particle of mass 6.63 g moving with a velocity of 100 ms–1 is :
[JEE(Main) 2014 Online (12-04-14), 4/120]
(1) 10–33 m (2) 10–35 m (3) 10–31 m (4) 10–25 m

6. Excited hydrogen atom emits light in the ultraviolet region at 2.47 × 1015 Hz With thi frequency, the
energy of a single photon is : (h = 6.63 × 10–34 Js) [JEE(Main) 2014 Online (12-04-14), 4/120]
(1) 8.041 × 10 J
–40 (2) 8.041 × 10 J–19 (3) 1.640 × 10–18 J (4) 6.111 × 10–17 J

7. Ionization energy of gaseous Na atom is 495.5 kJ mol–1. The lowest possible frequency of light that
ionizes a sodium atom is (h = 6.626 × 10–34 Js, NA = 6.022 × 1023 mol –1)
[JEE(Main) 2014 Online (19-04-14), 4/120]
(1) 7.50 × 104 s–1 (2) 4.76 × 1014 s–1 (3) 3.15 × 1015 s–1 (4) 1.24 × 1015 s–1

PHASOR ACADEMY Mob No: 9137061453 Page 14

Atomic Structure
8. If the principal quantum number n = 6, the correct sequence of filling of electrons will be :
[JEE(Main) 2015 Online (10-04-15), 4/120]
(1) ns→np→(n – 1)d→(n – 2)f (2) ns→(n – 1)d→(n – 2)f→np
(3) ns→(n – 2)f→np→(n – 1)d (4) ns→(n – 2)f→(n – 1)d→np

3
9. At temperatuere T, the average kinetic energy of any particle is KT. The de Broglie wavelength
2
follows the order : [JEE(Main) 2015 Online (11-04-15), 4/120]
(1) Visible photon > Thermal neutron > Thermal electron
(2) Thermal proton > Thermal electon > Visible photon
(3) Thermal proton > Visible photon > Thermal electron
(4) Visible photon > Thermal electron > Thermal neutron

10. The total number of orbitals associated with the principal quantum number 5 is:
[JEE(Main) 2016 Online (09-04-16), 4/120]
(1) 5 (2) 20 (3) 25 (4) 10

11. Aqueous solution of which salt will not contain ions with the electronic configuration 1s22s22p63s23p6 ?
[JEE(Main) 2016 Online (10-04-16), 4/120]
(1) NaCl (2) CaI2 (3) NaF (4) KBr

12. If the shortest wavelength in Lyman series of hydrogen atom is A, then the longest wavelength in
Paschen series of He+ is : [JEE(Main) 2017 Online (08-04-17), 4/120]
36A 9A 5A 36A
(1) (2) (3) (4)
5 5 9 7

13. The electron in the hydrogen atom undergoes transition from higher orbitals to orbitals of radius 211.6
pm. This transition is associated with : [JEE(Main) 2017 Online (09-04-17), 4/120]
(1) Paschen series (2) Brackett series (3) Lyman series (4) Balmer series

PART - II : JEE (ADVANCED) / IIT-JEE PROBLEMS (PREVIOUS YEARS)

* Marked Questions may have more than one correct option.
1. Rutherford’s experiment, which established the nuclear model of the atom, used a beam of :
[JEE 2002(S), 3/90]
(A) β-particles, which impinged on a metal foil & got absorbed.
(B) γ-rays, which impinged on a metal foil & ejected electrons.
(C) helium atoms, which impinged on a metal foil & got scattered.
(D) helium nuclei, which impinged on a metal foil & got scattered.

2. If nitrogen atom had electronic configuration 1s7, it would have energy lower than that of the normal
ground state configuration 1s2 2s2 2p3, because the electrons would be close to nucleus, yet 1s7 is not
observed because it violates : [JEE 2002(S), 3/90]
(A) Heisenberg uncertainty principle (B) Hund’s rule
(C) Pauli’s exclusion principle (D) Bohr’s postulate of stationary orbits.

3. The orbit having Bohr radius equal to 1st Bohr orbit of H–atom is [JEE 2004(S), 3/84]
(A) n = 2 of He+ (B) n = 2 of B+4 (C) n = 3 of Li+2 (D) n = 2 of Be+3

PHASOR ACADEMY Mob No: 9137061453 Page 15

Atomic Structure
4. Number of radial nodes in 3s and 2p orbitals (respectively) are : [JEE 2004(S), 3/84]
(A) 2, 0 (B) 2, 1 (C) 3, 2 (D) 2, 2

Paragraph for Question Nos. 5 to 7

The hydrogen-like species Li2+ is in a spherically symmetric state S1 with one radial node. Upon
absorbing light the ion undergoes transition to a state S2. The state S2 has one radial node and its
energy is equal to the ground state energy of the hydrogen atom.

5. The state S1 is : [JEE 2010, 3/163]

(A) 1s (B) 2s (C) 2p (D) 3s

6. Energy of the state S1 in units of the hydrogen atom ground state energy is : [JEE 2010, 3/163]
(A) 0.75 (B) 1.50 (C) 2.25 (D) 4.50

7. The orbital angular momentum quantum number of the state S2 is : [JEE 2010, 3/163]
(A) 0 (B) 1 (C) 2 (D) 3

8. Bombardment of aluminum by α-particle leads to its artificial disintegration in two ways, (I) and (ii) as
shown. Products X, Y and Z respectively are, [JEE 2011, 3/180]

(A) proton, neutron, positron (B) neutron, positron, proton

(C) proton, positron, neutron (D) positron, proton, neutron

9. The kinetic energy of an electron in the second Bohr orbit of a hydrogen atom is [a0 is Bohr radius] :
[JEE 2012, 3/136]
2 2 2 2
h h h h
(A) 2
(B) (C) (D)
4π ma02 16π 2
ma02 32π 2
ma02 64π 2ma02

10. P is the probability of finding the 1s electron of hydrogen atom in a spherical shell of infinitesimal
thickness, dr, at a distance r from the nucleus. The volume of this shell is 4πr2dr. The qualitative sketch
of the dependence of P on r is [JEE(Advanced) 2016, 3/124]
P P P P

(A) (B) (C) (D)

0 r 0 r 0 r 0 r

PHASOR ACADEMY Mob No: 9137061453 Page 16

Atomic Structure

Answer Q.11, Q.12 and Q.13 by appropriately matching the information given in the three
columns of the following table.
The wave function, ψn, l , ml is a mathematical function whose value depends upon spherical polar
coordinates (r, θ, φ) of the electron and characterized by the quantum numbers n, l and ml. Here r is
distance from nucleus, θ is colatitude and φ is azimuth. In the mathematical functions given in the
Table, Z is atomic number and ao is Bohr radius.
Column 1 Column 2 Column 3

3  Zr  ψn, l , ml (r)
(I) 1s orbital  Z  2 –  a 
(i) ψn, l , ml ∝   e  o  (P)
 ao 
0
r/ao
(Q) Probability density at nucleus
(II) 2s orbital (ii) One radial node 1
∝
a3o
5  Zr 
 Z  2 –  2a  (R) Probability density is
(III) 2pz orbital (iii) ψn, l , ml ∝   re  o  cosθ maximum at nucleus
 ao 
(S) Energy needed to excite
electron from n = 2 state to
27
n = 4 state is times the
(IV) 3dz orbital
2 (iv) xy-plane is a nodal plane 32
energy needed to excite
electron from n = 2 state to
n = 6 state

11. For He+ ion, the only INCORRECT combination is [JEE(Advanced) 2017, 3/122]
(A) (I) (i) (S) (B) (II) (ii) (Q) (C) (I) (iii) (R) (D) (I) (i) (R)

12. For the given orbital in Column 1, the only CORRECT combination for any hydrogen-like species is
[JEE(Advanced) 2017, 3/122]
(A) (II) (ii) (P) (B) (I) (ii) (S) (C) (IV) (iv) (R) (D) (III) (iii) (P)

13. For hydrogen atom, the only CORRECT combination is [JEE(Advanced) 2017, 3/122]
(A) (I) (i) (P) (B) (I) (iv) (R) (C) (II) (i) (Q) (D) (I) (i) (S)

PHASOR ACADEMY Mob No: 9137061453 Page 17

Atomic Structure

PART - III: NEET / AIPMT QUESTION (PREVIOUS YEARS )

* Marked Questions are having more than one correct option.
1. The energy of a photon is 3.03 × 10–19 J, then wavelength of this photon is:
(Given, h = 6.63 × 10–34 Js, c = 3.00 × 108 ms–1) [AIPMT 2000]
(1) 6.56 nm (2) 65.6 nm (3) 656 nm (4) 0.656 nm

2. Maximum number of orbitals in an atom which can have the quantum numbers n = 3, l = 2, m = + 2 are:
[AIPMT 2001]
(1) 1 (2) 2 (3) 3 (4) 4

3. Energy of first excited state in hydrogen atom is – 3.4 eV then, kinetic energy of electron in same orbit
of hydrogen atom is : [AIPMT 2002]
(1) + 3.4 eV (2) + 6.8 eV (3) – 13.6 eV (4) + 13.6 eV

4. The value of Planck's constant is 6.63  10–34 Js. The velocity of light is 3.0  108 ms–1. Which value is
closest to the wavelength in nanometers of a quantum of light with frequency of 8  1015 s–1 ?
[AIPMT 2003]
(1) 2  10–25
(2) 5  10–18
(3) 4  101
(4) 3  107

5. The frequency of the radiation emitted when the electron falls from n = 4 to n = 1 in a hydrogen atom
will be (Given ionization energy of H = 2.18  10–18 J atom–1 and h = 6.625  10–34 Js) [AIPMT 2004]
(1) 1.54  1015 s–1 (2) 1.03  1015 Js–1 (3) 3.08  1015 s–1 (4) 2.0  1015 s–1

6. Among the following transition metal ions, the one set where all the metal ions have 3d 2 electronic
configuration is [At Nos. Ti = 22, V = 23, Cr = 24, Mn = 25] [AIPMT 2004]
(1) Ti3+, V2+, Cr3+, Mn4+ (2) Ti4+, V4+, Cr+6, Mn7+ (3) Ti4+, V3+, Cr2+, Mn3+ (4) Ti2+, V3+, Cr4+, Mn5+

7. The energy of the second Bohr orbit of the hydrogen atom is –328 kJ mol–1 ; hence the energy of fourth
Bohr orbit would be [AIPMT 2005]
(1) – 1312 kJ mol–1 (2) – 82 kJ mol–1 (3) – 41 kJ mol–1 (4) – 164 kJ mol–1
8. The Uncertainity involved in the measurement of velocity of electron within a distance of 0.1 Å is :
(Given : The mass of electron is 9.11  10–31 kg, planck constant is 6.626  10–34 J s) [AIPMT 2006]
(1) 5.79  108 m s–1 (2) 5.79  105 m s–1 (3) 5.79  106 m s–1 (4) 5.79  107 m s–1

9. The orientation of an atomic orbital is governed by : [AIPMT 2007]

(1) azimuthal eqantum number (2) spin quantum number
(3) magnetic quantum number (4) principal quantum number
10. Consider the following sets of quantum numbers :
n l m s
(i) 3 0 0 +1/2
(ii) 2 2 1 +1/2
(iii) 4 3 –2 –1/2
(iv) 1 0 –1 –1/2
(v) 3 2 3 +1/2
Which of the following sets of quantum numbers is not possible ? [AIPMT 2007]
(1) (i) and (iii) (2) (ii), (iii) and (iv) (3) (i), (ii), (iii) and (iv) (4) (ii), (iv) and (v)

PHASOR ACADEMY Mob No: 9137061453 Page 18

Atomic Structure
11. The uncertainity in measurement position of the electron is associated with an uncertainity in
momentum, which is equal to 1 10–18 g cm s–1. The Uncertainity in electron velocity is, (mass of an
electron is 9  10–28 g) [AIPMT 2008]
(1) 1  10 cm s
9 –1
(2) 1  10 cm s
6 –1
(3) 1  10 cm s
5 –1
(4) 1  10 cm s–1
11

12. If the uncertainity in position and momentum are equal, then uncertainity in velocity is : [AIPMT 2008]
1 h h 1 h h
(1) (2) (3) (4)
2m  2 m  

13. Maximum number of electrons in a subshell of an atom in determined by the following : [AIPMT 2009]
(1) 4 l + 2 (2) 2 l + 1 (3) 4 l – 2 (4) 2 n2

14. A photon of energy 4.4 × 10–19 J collides with A2 molecules. If bond energy of A2 is 4.0 × 10–19 J. Then
kinetic energy of per atom of A will be : [AIPMT 2009]
(1) 2.0 × 10–20 J (2) 2.2 × 10–19 J (3) 2.0 × 10–19 J (4) 4.0 × 10–20 J

15. Which of the following is not permissible set of quantum numbers of electrons in an atom?
[AIPMT 2009]
(1) n = 4, l = 0, m = 0, s = – 1/2 (2) n = 5, l = 3, m = 0, s = + 1/2
(3) n = 3, l = 3, m = 0, s = – 1/2 (4) n = 3, l = 2, m = – 2, s = – 1/2

16. A 0.66 kg ball is moving with a speed of 100 m/s. The associated with ball wavelength will be : (h = 6.6
× 10–34 Js) [AIPMT 2010]
–32 –34 –35 –32
(1) 6.6 × 10 m (2) 6.6 × 10 m (3) 1.0 × 10 m (4) 1.0 × 10 m

17. The total number of atomic orbitals in fourth energy level of an atom are : [AIPMT 2011]
(1) 8 (2) 16 (3) 32 (4) 4

18. The energies E1 and E2 of two radiations are 25 eV and 50 eV respectively. The relation between their
wavelengths (i.e. 1 and 2) will be : [AIPMT 2011]
1
(1) 1 = 2 (2) 1 = 22 (3) 1 = 42 (4) 1 = 
2 2
19. If n = 6, the correct sequence for filling of electrons will be : [AIPMT 2011]
(1) ns  (n – 2)f  (n – 1)d  np (2) ns  (n – 1)d  (n – 2)f  np
(3) ns  (n – 2)f  np  (n – 1)d (4) ns  np(n – 1)d  (n – 2)f
20. According to the Bohr Theory, which of the following transitions in the hydrogen atom will give rise to
the least energetic photon ? [AIPMT 2011]
(1) n = 6 to n = 1 (2) n = 5 to n = 4 (3) n = 6 to n = 5 (4) n = 5 to n = 3
21. Maximum number of electrons in a subshell having n = 4 and  = 3 are : [AIPMT 2012]
(1) 14 (2) 16 (3) 10 (4) 12
22. The correct set of four quantum numbers for the valence elecron of rubidium atom (Z=37) is :
[AIPMT 2012]
(1) 5, 1, + 1/2 (2) 6, 0, 0 + 1/2 (3) 5, 0, 0 + 1/2 (4) 5, 1, 0 + 1/2

23. The orbital angular momentum of a p-electron is given as : [AIPMT 2012]

h h 3h h
(1) (2) 3 (3) (4) 6.
2 2 2 2

PHASOR ACADEMY Mob No: 9137061453 Page 19

Atomic Structure
36. Which one is the wrong statement ? [NEET- 2017]
h
(1) de-Broglie's wavelength is given by  = , where m = mass of the particle,  = group
m
velocity of the particle.
h
(2) The uncertainty principle is E × t 
4
(3) Half filled and fully filled orbitals have greater stability due to greater exchange energy,
greater symmetry and more balanced arrangement.
(4) The energy of 2s orbital is less than the energy of 2p orbital in case of Hydrogen like atoms.

37. Which one is a wrong statement? [NEET- 2018]

(1) Total orbital angular momentum of electron is 's' orbital is equal to zero.
(2) The value of m for dZ2 is zero.
1s2 2s2 2px1 2py 2pz1
1
(3) The electronic configuration of N atom is-
(4) An orbital is designated by three quantum numbers while an electron in an atomis designated by
four quantum numbers.

38. Which of the following series of transitions in the spectrum of hydrogen atom falls in visible region ?
[NEET-1- 2019]
(1) Brackett series (2) Lyman series (3) Balmer series (4) Paschen series

39. 4d, 5p, 5f and 6p orbitals are arranged in the order of decreasing energy. The correct option is :
[NEET-1- 2019]
(1) 5f > 6p > 4d > 5p (2) 5f > 6p > 5p > 4d (3) 6p > 5f > 5p > 4d (4) 6p > 5f > 4d > 5p
40. Orbital having 3 angular nodes and 3 total nodes is : [NEET-2- 2019]
(1) 5 p (2) 3 d (3) 4 f (4) 6 d

41. In hydrogen atom, the de Broglie wavelength of an electron in the second Bohr orbit is:
[Given that Bohr radius, a0 = 52.9 pm] [NEET-2- 2019]
(1) 211.6 pm (2) 211.6  pm (3) 52.9  pm (4) 105.8 pm

PHASOR ACADEMY Mob No: 9137061453 Page 20

Atomic Structure

EXERCISE - 1
A-1. (2) A-2. (4) A-3. (2) A-4. (1) A-5. (2)

A-6. (3) A-7. (2) A-8. (4) A-9. (2) A-10. (4)

A-11. (4) A-12. (2) A-13. (4) A-14. (3) A-15. (3)

A-16. (4) A-17. (3) A-18. (4) B-1. (1) B-2. (2)

B-3. (1) B-4. (3) B-5. (2) B-6. (4) B-7. (1)

B-8. (1) B-9. (1) B-10. (1) B-11. (1) B-12. (3)

C-1. (2) C-2. (3) C-3. (2) C-4. (3) C-5. (2)

C-6. (1) C-7. (3) C-8. (3) C-9. (2) C-10. (3)

C-11. (2) C-12. (3) C-13. (4) D-1. (3) D-2. (4)

D-3. (1) D-4. (1) D-5. (2) D-6. (3) D-7. (4)

D-8. (2) D-9. (4) D-10. (3) D-11. (1) D-12. (1)

D-13. (2) D-14. (4) D-15. (1) D-16. (1) D-17. (1)

D-18. (3) E-1. (4) E-2. (2) E-3. (3) E-4. (1)

E-5. (3) E-6. (3) E-7. (3) E-8. (4) E-9. (1)

E-10. (2) E-11. (1) E-12. (1) E-13. (1) E-14. (4)

E-15. (3) F-1. (2) F-2. (1) F-3. (1) F-4. (3)

F-5. (3) F-6. (4) F-7. (4) F-8. (4) F-9. (2)

F-10. (4) F-11. (1) F-12. (3) F-13. (3) F-14. (1)

F-15. (1) F-16. (4) F-17. (3) F-18. (3) F-19. (2)

EXERCISE - 2
PART - I
1. (4) 2. (3) 3. (2) 4. (3) 5. (1)

6. (3) 7. (3) 8. (2) 9. (4) 10. (3)

11. (3) 12. (2) 13. (4) 14. (4) 15. (2)

16. (2) 17. (2) 18. (3) 19. (1) 20. (4)

21. (1) 22. (1) 23. (3) 24. (2) 25. (3)

26. (2) 27. (1) 28. (1)

PHASOR ACADEMY Mob No: 9137061453 Page 21

 Atomic Structure

EXERCISE - 3
PART - I
OFFLINE JEE-MAIN

1. (1) 2. (3) 3. (1) 4. (1) 5. (2)

6. (4) 7. (2) 8. (2) 9. (1) 10. (3)

11. (2) 12. (1) 13. (1) 14. (3) 15. (4)

16. (1) 17. (1) 18. (3) 19. (4) 20. (1)

21. (1) 22. (2) 23. (4) 24. (2) 25. (3)

26. (1) 27. (2) 28. (1) 29. (1) 30. (3)

31. (3) 32. (3)

ONLINE JEE-MAIN

1. (3) 2. (3) 3. (1) 4. (4) 5. (1)

6. (3) 7. (4) 8. (4) 9. (4) 10. (3)

11. (3) 12. (4) 13. (4)

PART - II
1. (D) 2. (C) 3. (D) 4. (A) 5. (B)

6. (C) 7. (B) 8. (A) 9. (C) 10. (D)

11. (C) 12. (A) 13. (D)

PART-III

1. (3) 2. (1) 3. (1) 4. (3) 5. (3) 6. (4) 7. (2)

8. (3) 9. (3) 10. (4) 11. (1) 12. (1) 13. (1) 14. (1)

15. (3) 16. (3) 17. (2) 18. (2) 19. (1) 20. (3) 21. (1)

22. (3) 23. (1) 24. (2) 25. (3) 26. (3) 27. (1) 28. (4)

29. (2) 30. (4) 31. (1) 32. (4) 33. (1) 34. (2) 35. (4)

36. (4) 37. (3) 38. (3) 39. (2) 40. (3) 41. (2)

PHASOR ACADEMY Mob No: 9137061453 Page 22