Dept Of Chemistry

SREE SWAMI VIVEKANANDA COACHING CENTRE, BALLARI

(PUC-I, PUC-II, KCET/NEET/COMED-K/JEE COACHING CENTRE)
Innareddy Colony, 3rd Cross, Opposite Nexa Car Showroom, Ballari-583104

Topic: Structure of atom

1. Calculate the number of protons, neutrons and electrons in 8035Br.

1. p = 45, n = 35, e = 30 2. p = 45, n = 35, e = 80 3. p = 35, n = 45, e =35 4. p = 45, n = 35, e = 40
2. The number of electrons, protons and neutrons in a species are equal to 18, 16 and 16 respectively. Proper symbol
of the species is
32 2−¿ 24 2−¿ 16 2−¿ 32
1. 16S ¿ 2. 16 S ¿ 3. 8O ¿ 4. 16S
3. The Vividh Bharati station of All India Radio, Delhi, broadcasts on a frequency of 1,368 kHz (kilo hertz). The
wavelength of the electromagnetic radiation is
1. 229.3m 2. 119.3m 3. 219.3m 4. 429.3m
0
4. The frequency in s-1 of a radiation having a wavelength of 5800 A is
1. 5.172 x 1014 s-1 2. 5.172 x 1014 s-1 3. 3.520 x 1010 s-1 4. 3.520 x 1010 s-1
5. A 100 watt bulb emits monochromatic light of wavelength 400 nm. The number of photons emitted by the bulb
per second is
1. 2 x 1010 s-1 2. 2  1020 s-1 3. 3 x 1010 s-1 4. 3 x 1020 s-1
6. When electromagnetic radiation of wavelength 300 nm falls on the surface of sodium, electrons are emitted with a
kinetic energy of 1.68 x 105 J mol-1. What is the minimum energy needed to remove an electron from sodium?
1. 3.34 x 10-5 J mol-1 2. 4.10 x 10-3 J mol-1 3. 8.15 x I0-5J mol-1 4. 2.31 x 105 J mol-1
7. The mass of an electron is 9.1 x 10-31 kg. If its K.E. is 3.0 x 10-25 J, then its wavelength is
1. 896.7nm 2. 689.7nm 3. 500 nm 4. 725.0nm
8. A microscope using suitable photons is employed to locate an electron in an atom within a distance of 0.1 A.
What is the uncertainty involved in the measurement of its velocity?
1. 7.89 x 10-6 m s-1 2. 7.89  10-5 m s-1 3. 5.79  106 m s-1 4. 5.79 x 10-6 m s-1
9. A golf ball has a mass of 40 g and a speed of 45m/s. If the speed can be measured within accuracy of 2%. The
uncertainty in the position is
1. 2.45 x 10-30 m 2. 2.78 x 10-33 m 3. 1.46 x 10-33m 4. 4.75 x 10-20m
10. What is the total number of orbitals associated with the principal quantum number n = 3?
1. 4 2. 5 3. 8 4. 9
11. Yellow light emitted from a sodium lamp has a wavelength () of 580 nm. The wave number ( v ) of the yellow
light is
1. 1.724 x 106m-1 2. 4.724 x 10-6m-1 3. 2.5 x 10-7 m-1 4. 7.5 x 10-6 m-1
12. A photon of wavelength 4 x 10-7 m strikes on metal surface, the work function of the metal being 2.13 eV. The
energy of the photon (eV) is
1. 3.102 2. 4.104 3. 5.405 4. 7.305

PRAKASHGOWDA G, Lecturer in Chemistry, Ballari. Contact No: 9731434748

 Dept Of Chemistry

13. Electromagnetic radiation of wavelength 242 nm is just sufficient to ionise the sodium atom. The ionisation
energy of sodium in kJ mol-1 is
1. 498.65 kJ mol-1 2. 398.50 k J mol-1 3. 494.65 k J mol-1 4. 200.50 k J mol-1
14. What is the maximum number of emission lines when the excited electron of a H atom in n = 6 drops to the
ground state?
1. 15 2. 6 3. 13 4. 4
-18 -1
15. The energy associated with the first orbit in the hydrogen atom is -2.18 x 10 J atom . The energy associated
with the fifth orbit is
1. 18.7 x 10-20 J atom-1 2. -18.72 x 1020 J atom-1 3. -8.72 x 10-20 J atom-1 4. 5.38 x 10-10 J atom-1
16. Which of the following species are isoelectronic?
1. Na+, Mg, Ar 2. Na+, Mg2+, S2-, K+ 3. K+, Ca2+, S2-, Ar 4. Mg2+, S2-, K+
17. What is the wavelength of light emitted when the electron in a hydrogen atom undergoes transition from an
energy level with n = 4 to an energy level with n = 2?
1. 486nm 2. 648nm 3. 846nm 4. 468nm
18. Which of the following sets of quantum numbers is possible?
1. n = 1, l = 0, ml = 0, ms= -1/2 2. n = 2, l = 1, ml= 0, ms = -1/2
3. n = 3, l= 3, ml = -3, ms = + 1/2 4. n=3, l = I, ml = 0, ms = +1/2
19. In Millikan’s experiment, static electric charge on the oil drops has been obtained by shining X-rays. If the static
electric charge on the oil drop is - 1.282 x 10-18 C, the number of electrons present in it is
1. 5 2. 7 3. 10 4. 8
20. An ion with mass number 37 possesses one unit of negative charge. If the ion contains 11.1 % more neutrons than
electrons, the number of protons in ion is
1. 5 2. 10 3. 17 4. 18
21. Nitrogen laser produces a radiation at a wavelength of 337.1 nm. If the number of photons emitted is 5.6 x 10 24 the
power of this laser is
1. 2.3 x 106 J 2. 3.3  106 J 3. 4.3  10-7 J 4. 5.3 x 106 J
22. Lifetimes of the molecules in the excited states are often measured by using pulsed radiation source of duration
nearly in the nano second range. If the radiation source has the duration of 2ns and number of photons emitted
during the pulse source is 2.5 x 1015, the energy of the source is
1. 8.28 x 10-10 J 2. 8.28  1010 J 3. 5 x 109J 4. 82.8 x 105J
23. The ejection of the photoelectron from the silver metal in the photoelectric effect experiment can be stopped by
applying the voltage of 0.35 V when the radiation 256.7nm is used. The work function for silver metal is
1. 5.48 eV 2. 2.35 eV 3. 4.48eV 4. 7.35eV
24. Dual behaviour of matter proposed by de Broglie led to the discovery of electron microscope often used for the
highly magnified images of biological molecules and other type of material. If the velocity of the electron in this
microscope is 1.6 x 106 m s-1, the de Broglie wavelength associated with this electron is
1. 455pm 2. 222pm 3. 333 pm 4. 755 pm
25. How many electrons will be present in the sub-shells having ms value of -1/2 for n = 4?
1. 15 2. 10 3. 16 4. 25

PRAKASHGOWDA G, Lecturer in Chemistry, Ballari. Contact No: 9731434748

 Dept Of Chemistry

26. The total number of orbitals associated with the principal quantum number 5 is
1. 20 2. 25 3. 10 4. 5
27. Which of the following is the energy of a possible excited state of hydrogen?
1. 34eV 2. +6.8 eV 3. +13.6eV 4. -6.8eV
28. If the principal quantum number n = 6, the correct sequence of filling of electrons will be
1. ns  np  (n - 1)d  (n – 2)f 2. ns  (n – 2)f  (n - 1)d  np
3. ns  (n - 1)d (n – 2)f  np 4. ns  (n – 2)f  np  (n - 1)d
3
29. At temperature T, the average kinetic energy of any particle is kT. The de Broglie wavelength follows the order
2
1. Thermal proton > visible photon > thermal electron
2. Thermal proton > thermal electron > visible photon
3. Visible photon > thermal electron > thermal neutron
4. Visible photon > thermal neutron > thermal electron
30. The correct set of four quantum numbers for the valence electrons of rubidium atom (Z = 37) is
1 1 1 1
1. 5, 0, 1, + 2. 5, 0, 0, + 3. 5, 1, 0, + 4. 5, 1, 1, +
2 2 2 2

( )
2
Z
31. Energy of an electron is given by E = -2.178 x 10-18 J 2 . Wavelength of light required to excite an electron in
n
an hydrogen atom from level n = 1to n = 2 will be (h=6.62 x 10-34J s and c = 3.0 x 108ms-1)
1. 8.500 x 10-7m 2. 1.214 x 10-7m 3. 2.816 x 10-7m 4. 6.500 x 10-7m
32. The electrons identified by quantum numbers n and I:
1. n = 4, l= 1 2. n = 4, l = 0 3. n =3, l = 2 4. n = 3, l = 1
can be placed in order of increasing energy as
1. (4) < (2) < (3) < (1) 2. (2) < (4) < (1) < (3) 3. (1) < (3) < (2) < (4) 4. (3) < (4) < (2) < (1)
33. 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
1. 1035nm 2. 325nm 3. 743nm 4. 518nm
34. 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 x 108 ms-1 and NA = 6.02 x 1023 mol-1)
1. 494nm 2. 594nm 3. 640nm 4. 700nm
+ -18
35. Ionisation energy of He is 19.6 x 10 J atom . The energy of the first stationary state (n = 1) of Li2+ is
-1

1. 8.82 x 10-17 J atom-1 2. 4.41 x 10-16 J atom-1 3. - 4.41 x 10-17 J atom-1 4. - 2.2 x 10-15J atom-1
36. Calculate the wavelength (in nanometre) associated with a proton moving at 1.0 x 10 m s -1. (Mass of proton = 1.67
x 10-27 kg and h = 6.63 x 10-34 J s)
1. 0.032 nm 2. 0.40 nm 3. 2.5nm 4. 14.0nm
37. In an atom, an electron is moving with a speed of 600 m/s with an accuracy of 0.005%. Certainty with which the
position of the electron can be located is (h = 6.6 x 10-34 kg m2s-1, mass of electron, em, = 9.1 x 10-31 kg)
1. 1.52 x 10-4m 2. 5.10 x 10-3m 3. 1.92 x 10-3 m 4. 3.84 x 10-3 m
38. The ionization enthalpy of hydrogen atom is 1.312 x 106 J mol-1. The energy required to excite the electron
in the atom from n = I to n = 2 is
1. 9.84 x 105 J mol-1 2. 8.51 x 105 J mol-1 3. 6.56 x 105 Jmol-1 4. 7.56 x 105J mol-1

PRAKASHGOWDA G, Lecturer in Chemistry, Ballari. Contact No: 9731434748

 Dept Of Chemistry

39. Which of the following sets of quantum numbers represents the highest energy of an atom?
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
40. 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
41. Which one of the following sets of quantum number represents an impossible arrangement?
n 1 m1 ms
1. 3 2 -2 1/2
2. 4 0 0 1/2
3. 3 2 -3 1/2
4. 5 3 0 1/2
42. The orbital diagram in which Aufbau principle is violated is

43. The quantum number not obtained from the Schrodinger’s wave equation is
1. n 2. l 3. M 4. S
44. Pick out the isoelectronic structures from the following
(i) CH3+ (ii) H3O+ (iii) NH3 (iv) CH3-
1. (i) and (ii) 2. (iii) and (iv) 3. (i) and (iii) 4. (ii), (iii) and (iv)
45. Which of the following is violation of Pauli's exclusion principle?

46. Which of the following has maximum number of unpaired electron?

1. Mg2+ 2. Ti3+ 3. V3+ 4. Fe2+
47. The electrons identified by quantum number n and I, (i) n = 4, l = 1 (ii) n = 4, l = 0 (iii) n = 3, l = 2 (iv) n = 3,
l = 1 can be placed in order of increasing energy, from the lowest to highest, as
1. (iv) < (ii) < (iii) < (i) 2. (ii) < (iv) < (i) < (iii) 3. (i) < (iii) < (ii) < (iv) 4. (iii) < (i) < (iv) < (ii)
48. For how many orbitals, the quantum numbers n = 3, l=2, m = + 2 are possible?
1. 1 2. 2 3. 3 4. 4
49. The nineteenth electron of chromium has which of following set of quantum number?
n l m s
1. 3 0 0 1/2
2. 3 2 -2 1/2
3. 4 0 0 1/2
4. 4 1 -1 1/2
50. The correct order of increasing energy of atomic orbitals is
1. 5p < 41 < 6s < 5d 2. 5p < 6s < 4f< 5d 3. 41< 5p < 5d< 6s 4. 5p < 5d < 4f < 6s

PRAKASHGOWDA G, Lecturer in Chemistry, Ballari. Contact No: 9731434748

 Dept Of Chemistry

Homework (dpp)

1. Visible spectrum extends from 400 nm (violet) to 750 nm (red). Hence frequency ratio is
1. 4/15 2. 8/15 3. 15/8 4. 3/15
-1
2. One of the lines in the spectrum of atomic hydrogen has wave number 533.16 cm . What is the frequency of this
line?
1. 5.623 x 106 s-1 2. 1.876 x 10 s-1 3. 1.598 x 1013 s-1 4. 1.598 x 1014 s-1
3. Calculate the number of photons of light of wavelength 3960 A necessary to provide 1 J of energy
1. 2 x 1020 2. 2 x 1016 3. 2 x 1015 4. 2 x 1018
4. The accelerating potential that must be imparted to a proton beam to give it an effective wavelength of 0.05 nm is
(wt. of proton = 1.008 g)
1. 0.325V 2. 5.205V 3. 52.05V 4. 3.25V
5. Number of photons emitted in 5 hours by a 50 W sodium lamp is (photon = 5893 A0).
1. 7.4 x 1020 2. 4.46 x 1022 3. 2.7 x 1024 4. 5.4 x 1023
6. Binding energy of electrons in a metal is 250 kJ mol-1. Then threshold frequency of metal is
1. 3.8 x 1038 s-1 2. 3.8 x 1035 s-1 3. 6.3 x 1011 s-1 4. 6.3 x 1014 s-1
7. Heaviest particle is
1. Meson 2. Neutron 3. Proton 4. Electron
8. An -particle is identical with
1. Proton 2. Neutron 3. Helium nucleus 4. Electron
9. The triad of nuclei which is isotonic is
1. 6C14, 7N15, 9F17 2. 6C12, 7N14, 9F19 3. 6C14, 7N14, 9F17 4. 6C14, 7N14, 9F19
10. Electromagnetic radiation with maximum wavelength is
1. Ultra-violet 2. Radiowave 3. X-rays 4. Infrared
11. As we move away from nucleus, the energy of orbit
1. Decreases 2. Increases 3. Remains unchanged 4. None of these
12. The radius of the atom is of the order of
1. 10-10 cm 2. 10-13 cm 3. 10-15 cm 4. 10-8 cm
13. 1 erg of energy corresponds to
1. 6.02 x 1023 J/mol 2. 6.02 x 1016 J/mol 3. 1 erg/mol 4. 10-7 J/mol
14. Sodium chloride imparts a yellow colour to the Bunsen flame. This can be interpreted due to the
1. Low ionization energy of sodium
2. Sublimation of metallic sodium to give yellow vapour
3. Emission of excess energy absorbed as a radiation in the visible region
4. Photosensitivity of sodium
15. With increasing principal quantum number, the energy difference between adjacent energy levels in H atom
1. Decreases 2. Increases 3. Remains constant
4. Decreases for low value of Z and increases for higher value of Z.
16. Splitting of spectral lines under the influence of magnetic field is called
1. Stark effect 2. Zeeman effect 3. Photoelectric effect 4. None of these

PRAKASHGOWDA G, Lecturer in Chemistry, Ballari. Contact No: 9731434748

 Dept Of Chemistry

17. If r is the radius of first orbit, the radius of nth orbit of the H atom will be
1. r n2 2. r n 3. r/n 4. r 2n2
18. If the radius of first Bohr's orbit be a0, then the radius of third Bohr’s orbit would be
1. 3 x a0 2. 6 x a0 3. 9 x a0 4. 1/9 x a0
19. The electron in an atom
1. Moves randomly around the nucleus 2. Has fixed space around the nucleus
3. Is stationary in various energy levels 4. Moves around its nucleus in definite energy levels.
20. The value of Planck’s constant is
1. 6.6256 x 10-27 erg s 2. 66.256 x 10-27 erg s 3. 6.02 x 10-15 erg s 4. 3.01 x 1023 erg s
21. The radius of hydrogen atom in the ground state is 0.53 A0, the radius of 3Li2+ in the similar state is
1. 1.06 A0 2. 0.265 A0 3. 0.17 A0 4. 0.53 A0
22. Who modified Bohr’s theory by introducing elliptical orbit, for electron path?
1. Hund 2. Thomson 3. Rutherford 4. Sommerfeld
23. The third line of the Balmer series, in the emission spectrum of the hydrogen atom, is due to the transition from
the
1. Fourth Bohr orbit to the first Bohr orbit 2. Fifth Bohr orbit to the second Bohr orbit
3. Sixth Bohr orbit to the third Bohr orbit 4. Seventh Bohr orbit to the third Bohr orbit
24. Which of the following expressions gives the de-Broglie relationship?
h h h v
1. =p 2.  = 3.  = 4. m =
mv mv mp p
25. Wave nature of electrons was demonstrated by
1. Schrodinger 2. de-Broglie 3. Davisson 4. Heisenberg
26. The equation x. p  h/4 shows
1. de-Broglie relation 2. Heisenberg’s uncertainty principle 3. Aufbau principle 4. Hund’s rule
27. At 2000C hydrogen molecules have velocity 105 cm s-1 . The de-Broglie wavelength in this case is approximately
0 0 0 0
1. 2 A 2. 1000 A 3. 100 A 4. 10 A
28. If uncertainty in the position of electron is zero, the uncertainty in its momentum would be
h h
1. Zero 2.  3. < 4. Infinite
4π 4π
29. The uncertainty in the momentum of an electron is 1.0 x 10-5 kg m s-1. The uncertainty in its position will be
(h = 6.62 x 10-34 kg m2s-1)
1. 1.05 x 10-28 m 2. 1.05 x 10-26 m 3. 5.27 x 10-30m 4. 5.25 x 10-28m
30. The uncertainty in the position of an electron (mass 9.1 x 10-28 g) moving with a velocity of 3.0 x 104 cm s-1
accurate up to 0.011 % will be
1. 1.92cm 2. 7.68cm 3. 0.175cm 4. 3.84cm
31. The de-Broglie wavelength of a particle with mass 1 g and velocity 100 m/s is
1. 6.6  10-33 m 2. 6.6 x 10-34m 3. 6.6  10-35 m 4. 6.6 x 10-35 m
32. The magnetic quantum number represents
1. Size of the orbital 2. Spin angular momentum
3. Orbital angular momentum 4. Spatial orientation of orbital

PRAKASHGOWDA G, Lecturer in Chemistry, Ballari. Contact No: 9731434748

 Dept Of Chemistry

33. The principal quantum number, n describes

1. Shape of orbital 2. Subshell of electron 3. Main energy shell of electron 4. Spin of electron
34. Subsidiary quantum number specifies
1. Size of orbital 2. Shape of orbital 3. Orientations of orbital 4. Nuclear stability
35. No two electrons in an atom will have all the four quantum numbers same. This statement is known as
1. Pauli's exclusion principle 2. Uncertainty principle
3. Hund’s rule 4. Aufbau principle
36. “The exact path of electron in 2p-orbital cannot be determined”. The above statement is based upon
1. Hund's rule 2. Bohr’s rule 3. Uncertainty principle 4. Aufbau principle
37. No two electrons in an atom can have
1. The same principal quantum numbers 2. The same azimuthal quantum numbers
3. The same magnetic quantum numbers 4. An identical set of four quantum numbers
38. Azimuthal quantum number determines the
1. Size 2. Spin 3. Orientation 4. Angular momentum of orbitals
39. In a set of degenerate orbitals the electrons distribute themselves to retain similar spins as far as possible. This
statement is attributed to
1. Pauli’s exclusion principle 2. Aufbau principle 3. Hund’s rule 4. Slaters
rules
40. The total number of orbitals in a shell with principal quantum number ‘n’ is
1. 2n 2. 2n2 3. n2 4. n + 1
41. The electronic configuration of an atom/ion can be defined by the following
1. Aufbau principle 2. Pauli’s exclusion principle 3. Hund’s rule 4. All the above
42. Which of the following orbitals have a dumb-bell shape?
1. s 2. p 3. d 4. F
43. A 4f orbital has
1. One node 2. Two nodes 3. Three nodes 4. Four nodes
44. The number of electrons in the M shell of the elements with atomic number 24 is
1. 24 2. 12 3. 13 4. 8
45. 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
46. For a given principal level n = 4, the energy of its sub-shells is of the order
1. s < d < f < p 2. s < p < d < f 3. d < f < p < s 4. s < p < f < d
47.
48. Which of the following has more unpaired d-electrons?
1. Zn+ 2. Fe2+ 3. Ni3+ 4. Cu+
49. The correct set of quantum numbers for 4d-electrons is
1. 4, 3, 2, + ½ 2. 4, 2, 1, 0 3. 4, 3, -2, +1/2 4. 4, 2, 1, -1/2
50. The element with electronic configuration of atom 1s22s22p63s23p63d104s1 is
1. Fe 2. Cu 3. Ni 4. Zn

PRAKASHGOWDA G, Lecturer in Chemistry, Ballari. Contact No: 9731434748