I

128 I G.R.B. PHYSICAL CHEMISTRY FOR COMPETITIONS

(iii) n =: 2, I I, m =: I (iv) n =: 3, I=: 2, m =: I 13127. Any p-orbital can accommodate up to: (MLNR 1990)
(v) n =: 3, I ::= 2, m =: 0 (a) 4 electrons
(a) (i) and (ii) (b) (ii) and (iii) (b) 2 electrons with parallel spins
1 (c) (iii) and (iv) (d) (iv) and (v) (c) 6 electrons
115. Which of the ions is not having the configuration ofNe? (d) 2 electrons with opposite spins
(a) Cl- (b) F - (c) Na + (d) Mg2+ 14 128. How'many electrons can fit into the orbitals that comprise the
2 116. Which ofthe following has the maximum number of unpaired 3rd quantum shell n =: 3?
d-electrons? (KeET 2008) (a) 2 (b) 8 . (c) 18 (d) 32
3 2 15129. The total number of orbitals in a principal shell is:
(a) Ni + (b)Cu+ (c)Zn2+ (d) Fe +
3117." Which of the following expressions gives the de Broglie (a) n (b) n2 (c) 2n 2 (d) 3n 2
relationship? IJEE (WB) 2008) 16130. Two electrons in K-shell will differ in:
h h (a) principal quantum number
(a) p =: - (b) A
mv mv (b) spin quantum number
(c) A =: h
h (c) azimuthal quantum number .
(d) Am=
mp p (d) magnetic quantum number .
4118. The principal quantum number of an atom is related to the: 17131. Which one of the following orbitals has the shape of a
(MLNR 1990) baby-boother ?
(a) size of the orbital (a) dxy (b) d x 2 - y 2 (c) d z 2 (d) Py
(b) orbitafangular momentum
(c) spin angular momentum
18 132. Which one of the following represents an impossible
arrangement? (AIEEE 2009)
(d) orien.tation ofthe orbital in space n I m s n I m s
5119. The magnetic quantum is a number related to:
(a) 3 2 - 2 112 (b) 4 0 o 1/2
(a) size (b) shape
(c) 3 2 . -3 112 (d) 5 3 o 112
(c) orientation (d) spin
6 120. The principal quantuIn number represents: (CPMT 1991) 19
(a) shape of an orbital
(b) nU!l).ber of in an orbit
(c) distance of electron from nucleus
(d) numbei: of orbitals in an orbit
7 121. The quantum number not obtained from the Schrodinger's
20
wave equation is: (lIT 1990)
(a) n (b) 1 (c) m (d) s
8 122. In a given atom, no two electrons can have the same values for
all the four quantum nU!l).bers. This is called: (CPMT 1990)
(a) Hund's rule (b) Pauli's exclusion principle
(c) Uncertainty principle (d) aufbau principle
9 123. The atomic orbital is: 21
(a) the circular path of the electron
(b) elliptical shaped orbit .
(c) three-dimensional field around nucleus
(c) 21 + I (d) 41 + 2
. (d) the region in which there is maximum probability· of
finding an electron [Hint: Number of electrons with same spin
10·124. If the ionization energy for hydrogen atom is 13.6 eV, then the 1 x Total no. of electrons
ionization energy for He+ ion should be: 2
1 .
I PMT (Haryana) 2004] =: - x 2 (21 + 1) =: (21 + 1)]
(a) 13.6 eV (b) 6.8 eV 2
(c) 54.4 eV (d) 72.2 eV 22 136.. Which of the following represents the correct set of four
11 125. Principal,. azimuthal and magnetic quantum numbers are quantum numbers of a 4d-e1ectron? (MLNR 1992)
respectively related to: (a) 4,3,2, + 112 (b) 4,2, 1,0
(a) si?e,shape and orientation (c) 4,3, - 2, + 112 (d) 4,2, i, 1/2
.(b) shape, size and orientation 23 137. Values of magnetic orbital quantum number for an electron of
(c) size, orientation and shape M-shell can be: (PET (Raj.) 2008]
(d) none of the above (a) 0, 1,2 (b)-2,-1,0,+1,+2
12126. Energy of e1ectron·in the H-atom is determined by : (c) 0, 1,2,3 (d) 1,0,+1
(a) only n (b) bothn and I 24138. Correct set of four quantum numbers for the outermost
(c) n, I and m (d) all the four quantum numbers . electron of rubidium (Z = 37) is:
 ATOMIC STRUCTURE 129

(a) 5,0,0,1/2 (b) 5, 1,0, 112 35 149• The energy of 2p y' orbital is:
.(c) 5,1, 1.112 (d) 6,0,0,112 (a) greater than 2px orbital
25 139. Which one of the following subshells is spherical in shape? (b) less than 2pz orbital
(a) 4s (b) 4p (c) 4d (d) 4f (c) equalto 2sorbitil
26140. In hydrogen atom, the electron is at a distance of 4.768 A from (d) same as that of2px and 2pz orbitals
the nucleus. The angular momentum of the electron is : 36150• The two electrons occupying the same orbital are
. [EAMCET (Med.) 2010] distinguished by: .
(a)· 3h . (b) (a) principal quantum.number
211: 211: (b) azimuthal quantum number
h (d) 3h (c) magnetic quantum number
(c) -
11: 11: (d) spin quantum number
n2 37 151. The maximum number of electrons in a subshell is given by
[Hint: r = - x 0.529 A
z the expression: (AIEEE 2009)
n2 (a) 41 + 2 (b) 4/- 2
4.768 = x 0.529
1 (c) ()./ + I (d) 2n2
n=3 152. The electronic configuration of an atom/ion can be defined by
nh __ 3h] 38 which of the following1
:. Angular m()mentum (mvr)
211: 211: (a) A1.dbau PriI1ciple
27 141. Total number of m values for n 4 is: (b) Pauli's exclusion principle
(a) 8 (b) 16 (c) 12 (d) 20 (c) Hund's rule of maximum mUltiplicity
28 142. What is the total number of orbitals in the shell to which the (d) All of the above
g-subshell first arise?
(a) 9 (b) 16 (c) 25 . (d)36 39 153. An electron has a spin quantum number + 112 and a magnetic
quantum number 1. It cannot be present in:
[Hint: For g-subshell, / = 4 (a) d-orbital (b).forbital (c) s-orbital (d) p-orbital
:. It will arise in 5th shell. 40 154. The value of azimuthal quantum number for electrons present
Total number of orbitals in 5th shell == n2 = 25] in 4 p-orbitals is:
29 143. In Bohr's model, if the atomic radius of the first orbit 1j, then (a) 1
radius offourth orbit will be : [BHU (Screening) 2010] (b) 2

(a) 4'1 (b) 6'1 (c) 161j(d) !L

°
(c) any value between and 3 except I
16 (d) zero
30144. Which of the following statements is not correct for an 41155. For the energy levels in an atom which one of the following
electron that has quantum numbers n = 4 and m = 2? statements is correct?
(MLNR 1993) (a) The 4s sub-energy level is at a higher energy than the 3d
, (a) The electron may have the q. no. I = + 1/2 sub-energy level
(b) The electron may have the q. no. I = 2 (b) The M -energy level can have maximum of 32 electrons
(c) The electron may have the q. no. 1= 3 (c) The second principal energy level can have four orbitals
(d) The electron may have the q. no. I = 0, I, 2, 3 and contain a maximum of 8 electrons
31 145. The angular momentum of an electron depends on: (d) The 5th main energy level can have maximum of 50
(a) principal quantum number electrons
42156. A new electron enters the orbital when:
(b) azimuthal quantum nwnber
( c) magnetic quantum number (a) (n + /)is minimwn (b) {n + J)is maximum
(d) all of the above (c) (n+m)isminimum (d) (n+m)ismaximum
32146. The correct set of quantum numbers for the unpaired electron 43 157. For a given value of n{principal quantum number), the energy
of a chlorine atom is: (DPMT 2009) of different subshells can be arranged in the order of: .
1 I (a) !>d> p>s (b) s> p>d>!
(a) 2,0,0, + (b) 2, I, -1, + (c)!>p>d>s (d)s>!>p>d
2 2 44158. After filling the 4d-orbitals, an electron will enter in:
I 1
(c) 3,1, I,±- (d) 3,0,O,±- (a) 4p (b) 4s (c) 5p (d) 4f
2 2
45159. According to t\ufbau principle, the correct order of energy of
33147. The magnetic quantum number for valency electron of sodium
atom is:
3d,4s and 4 p-orbitals is: [eEl' (J&K) 2006)
(a) 3 (b) 2 (c) I (d) zero (a) 4p<3d<4s (b) 4s<4p<3d
(c) 4s < 3d < 4 p (d) 3d < 4s < 4 p
34148. The shape of the orbital is given by: [PET (Raj.) 2008J
(a) spin quantum number 46 160. Number of p-electrons in bromine atom is:
(b) magnetic quantum number [PMT (Haryana) 20041
.(c) azimuthal quantum number (a) 12 (b) 15
(d) principal quantum number (c) 7 (d) 17
 130 G.R.B. PHYSICAL CHEMISTRY FOR COMPETITIONS

l
47 161. [Ar] 3dlO 4s electronic configuration belongs to: . 55169. The radial probability distribuuon curve obtained for an
[PET (MP) 20081 orbital wave function ('If) has 3 reaks and 2 radial nodes. The
(a) Ti (b) Tl (c) Cu (d) V valence electron of which one of the following metals does
48 162. How many unpaired electrons are in Ni2+ ? (Z 28) this wave function ('If ) correspond to ?
(a) Zero (b) 8 (c) 2 (d) 4 [EAMCET (Med.) 20101
49 163. The electronic configuration of chromium (Z 24) is: (a) Co (b) Li (c) K (d) Na
[PMT (MP) 1993; BHU (Pre.) 20051 [Hint: Na ll ls2, 2s22l, 3s 1
'----v----'
(a) [Ne] 3i3 p 6 3d 44i (b) [Ne] 3s2 3p 6 3d 54s1 Valence electron
Number of radial node =: n-l-I (n == 3)
(c) [Ne] 3i3p 6 3d l 4i (d) [Ne] 3i 3p64i4p4
3-0-1 = 2]
50 164. The number of d-electrons in Fe 2+ (At. No. 26) is not equal to 56 170.
(At. No. 36) has the electronic configuration [A]
that of the: (MLNR 1993) 4s 3d 104 p 6. The 37th electron will go into which one of the
(a) p-electrons in Ne (At. No. 10) . following sub-levels?
(b) s-electrons in Mg (At. No. 12) (a) 4/ (b) 4d
(c) d-electrons in Fe atom (c) 3p (d) 5s
(d) p -electrons in Cl- ion (At. No. 17) 57 171. An ion which has 18 electrons in the outermost shell is:
51 165. If the electronic structure of oxygen atom is written as (CBSE 1990)
f--2p---+ (a) K + Q » Cu.+ (c) Cs+ (d) Th 4 +
58172: Which ofthe following has non-spherical shell of electronJa
ls2, 2s2 !i.j, 1i.j, 1 . 1; it would violate: fISC (Bihar) 1993]
(lIT 1993)
(a) Hund's rule (a) He (b) B (c) Be (d) Li
59 173.
(b) Pauli's exclusion principle Which one of the following sets of quantum numbers is not
possible for an electron in the ground state of an atom with
(c) both Hund's and Pauli'sprincipJes
atomic number 19? [PET (Kerala) 2006;
52 (d) none of the above
CET (Karnataka) 2009]
166. The orbital diagram in which 'aufbau principle' is violated,is:
(a) n = 2, I 0, m == 0 (b) n = 2, I = 1, m 0
2s f - - 2 p---+
(c) n = 3, I =: I, m -1 (d) n 3,1=2,m=± 2
(a) [ill I i.j,1 i I (e) n 4,1=0,m=0
60 174. Helium nucleus is composed of two protons and two neutrons.
(b) If the atomic mass is 4.00388, how much energy is released
when the nucleus is constituted?
(c) :1 i.j, i (Mass of proton == 1.00757, Mass of neutron == 1.00893)
(a) 283 MeV (b) 28.3 MeV
(d) :1 i.j, :1 (c) 2830 MeV (d) 2.83 MeV
61 175. Binding energy per nucleon of three nuclei A, B and Care
53 167. The manganese (Z = 25)has the outer configuration: 5.5, 8.5 and 7.5 respectively. Which one of the following
4s ( 3p ) nuclei is most stable?
(a) [ill i i.j, II i il i l i II i !I (a) A (b) C
(c) B (d) Cannot be predicted
(b) [ill 62 176. The mass of jLi is 0.042 less than the mass of 3 protons and
4 neutrons. The binding energy per nucleon in j Li is:
(c) (ill :1 i .j, il j.j, :1 i .(BHU1992)
(a) 5:6 MeV (b) 56 MeV (c) 0.56 MeV (d) 560 MeV
(d) 0 II j.j, II i.j, II i i i 63 177. Meson was discovered by:
(a) Powell (b) Seaborg
54 168. Which of the following elements is represented by the (c) Anderson (d) Yukawa
electronic configuration? 64 178.. In most stable elements, the number of protons and neutrons
f--2p-c-? are:
(a) odd-odd (b) even-even
(c) odd-even (d) even-odd
65 179. Nuclear particles responsible for holding all nucleons together
are:
(a) electrons (b) neutrons
(c) positrons (d) mesons
(a) Nitrogen (b) Fluorine 66 The introduction of a neutron into the nuclear composition of
(c) Oxygen (d) Neon an atom would lead to a change in: (MLNR 1995)
 ATOMIC STRUCTURE 1.131
(a) its atomic inass (a) 3 (b) 4 (c) 2 (d) 1
(b) its atomic number 78 191. A certain negative ion has in its nucleus 18 neutrons,and
(c) the chemical nature of the atom 18 electrons in its extranuclear structure. What is the mass
(d) number of the electron also number of the most abundant isotope of X ?
181. Which of the following has highest orbital angular (a) 36 (b) 35.46 (c) 32 (d) 39
67 momentum? 79 193. Which of the following statements is not correct?
(a) 4s (b) 4p (c) 4d (d) 4f
(a) The shape of an atomic orbital depends on the azimuthal
68 181. Which of the following has maximum number of unpaired quantum number .
electrons? (PMT (Raj.) 2004; BHU (Pre.) 2005)
(b) The orientation of an atomic orbital depends on the
(a) (b) Fe 2+ (c) C0 2+ (d) C0 3+ magnetic quantum number
69 183. An electron isnot deflected on passing through a certain (c) The of an electron in an atomic orbital of
region,because: multielectron atom depends on the principal : quantum
(a) there is no magnetic field in that region number
(b) there is a magnetic field but velocity of the electron is (d) The number of degenerate atomic orbitals of one type
parallel to the direction of magnetic field depends on the values of azimuthal and magnetic qUa)1tum
(c) the electron is a chargeless particle numbers
(d) none ofthe aboye 80 194. Gases begin to conduct electricity at low pressure because:
70 184. In MiHik1m's oil drop experiment, we of:
(CSSE 1994)
(a) Ohm's law (b) Ampere's law (a) at low pressures gases tum to plasma
(c) Stoke's law (d) Faraday's law .(b) colliding electrons can acquire higher kinetic energy due to
71 185. A strong argument for the particle nature of cathode rays is: increased mean free path leading to ionisation of atoms
(a) they can propagate in vacuum (c) atoms break up into electrons and protons
(b) they produce fluorescence (d) the electrons in atoms can move freely at low pressure
(c) they cast shadows
81 195. An electron of mass m and charge e, is accelerated from rest
(d) they are deflected by electric and magnetic fields through a potential difference V in vacuum. Its final speed will
72 186. .As the speed of the electrons increases, the measured value of be: (eBSE W94)
charge to mass ratio (in the relativistic units):
(a) increases (a) (b) 2eVIm
(b) remains unchanged (c) J(eVI2m) (d) J(2eVlm)
(c) decreases .
(d) first increases and then decreases 82 196. The difference in angular momentum associated with .the
electron in the two successive orbits of hydrogen atom is:
73 187. Which of the following are true for cathode rays?
(a) It travels along a straight line (a) hln (b) hl2n (c) hl2 (d) (n -1)hI2lt
(b) It emits X -rays when strikes a metal 83 197. Photoelectric effect can be explained by assuming that light:
(c) It is an electromagnetic wave (a) is a form of transverse waves
(d) It is not deflected by magnetic field (b) is a form of longitudinal waves
74 ISS. Three isotopes of an element have masl' numbers, M, (M + 1) (c) can be polarised
and (M + 2). If the mean mass number is (M + 0.5) then
which of the following ratios may be accepted for (d) consists of quanta .
M, (M + 1), (M + 2)in that order? 84 198. The photoelectric effect supports quantum nature of Jight
(a) I : 1 : I (b) 4: 1 : 1
because:
(a) there is a minimum frequency of light below which no
(c) 3 : 2 : 1 (d) 2 : 1 : 1
photoelectrons are emitted .
75 189. The radii of two of the first four Bohr orbits of the hydrogen (b) the maximum kinetic energy of p\1otoelectrons depends
atom are in the ratio I : 4. The energy difference between them
only on the frequency oflight and not on its intensity
maybe: . .. .
(a) either 12.09 eV or 3.4 eV (6) .either 2.55 eV or 10.2 eV (c) even whet! metal surface is faintly illuminated the
photoelectrons leave the surface immediately
(c) either 13.6 eV or 3.4 eV (d) either 3.4 eV or 0.85 eV
(d) electric charge of photoelectrons is quanti sed
76 190. Photoelectric emission is .observed from a surface. for
frequencies VI and v 2 ofthe incidentradiafion (VI> V2 ).Ifthe 85199. The mass ofa proton at rest is: .(CB.SE 1991)
35
maximum kinetic energies of the photoelectrons in the two (a) zero (b) 1.67 x 10-:- kg
cases are in the ratio 1 : k then the threshold frequency V 0 is (c) one amu (d) 9 x 10-31 kg
given by:
86 200. Momentum of a photon of wavelength A is: (eBSE 1993)
(a) v 2 - VI (b) k VI (c) _k--=.._..!.. (d) v 2 - VI 2
k-l k-l k k (a) hlA (b) zero (c) hAle (d) hAle
77191. The number of waves made by a l30hr electron in an orbit of 87201. When X-rays pass through air they:
maximum magnetic quantum number +2 is: . ( a) produce light track in the air
(b) ionise the gas
.....
132 G.R.B. PHYSlpAL .FOR COMPETITIONS

(c) produce fumes in the air h

(a) L= nh (b) L= 1(1+1)-
(d) accelerate gas atoms. 2n 2n
88 202. X.rays:· (CPMT 1991) mg h
(a) are deflected in a magnetic field (c) L= (d) L=-
2n . 4n
(b) are deflected in an electric field
100214. Ground state electronic configuration of nitrogen atom can be
(c) remain undeflected by both the fields
represented by: (lIT 1999)
(d) are deflected in both the fields
89 203. Find the frequency of light that corresponds to photons of
energy 5.0x 10-5 erg: (AIIMS 2010)
1. [ill DIJ 11 11 11 I 2. ill] [ill 11 1 11 1
(a) 7.5xlO-21 sec-1
(c) 7.5xl02 1
(b) 7.5 x 10-21 sec
(d) 7.5 x 1&1 sec
3. DO l!J 11 I I 1 4. [!] [!] 1J 1J 1J 1
E 5xlO-s erg (a) 1 only (b) 1,2 only (c) 1,4 only (d) 2,3 only
[Hlnt:v=-= . 101215. Which of the following statement{s) are correct?
. h 6.63 X 10-27 erg sec
1. Electronic configuration ofCr is [Ar] 3d 5481 (At. No. of
= 7.54 xl02 1 sec-I]
Cr=24)
90 204. The energy of an electron in the flISt Bohr orbit of H·atom is 2. The magnetic quantum number may have negative value
-:-13.6 eV. The possible energy value(s) of the excited state(s)
3. In silver atom, 23 electrons have a spin of one type and 24
for in Bohr orbits of hydrogen is/are: (lIT 1998)
of the opposite type (At. 47L _.........__. ___ _
(a) ..:.3.4 tV (b) - 4.2 eV 4. The oxidation state. of nitrogen in HN3 is -3 (lIT 1998)
(c) -6.8 eV (d) +6.8 eV (a) 1,2,3 (b) 2,3:4 (c) 3,4 (d) 1,2,4
91 205. The electrons identified by quantum numbers n and I, (i) n == 4, 102 216. The electronic configuration of an element is
1= 1 Oi) n = 4, 1= 0 (iii) n = 3, I = 2 (iv) n = 3,1 = 1 can be ls22i 2p6, 3i 3p6 3d 5, 4}. This represents: (lIT 2000)
placed in order of increasing energy, from the lowest to highest . (a) excited state (b) ground state
as: (lIT 1999) (c) cationic state (d) anionic state
(a) (iv) < (ii) < (iii) < (i) (b) (ii) < (iv) < (i) < (iii) 103217. The quantum numbers + 1 and for the electron spin
(c) (i) < (iii) < (ii) < (iv) (d) (iii) < (i) < (iv) < (ii) represents: 2 2 (liT 2000)
92 206. The wavelength of the radiation emitted when an electron falls (a) rotation of the electron in clockwise and anticlockwise
from Bohr orbit 4 to 2 in hydrogen atom is: (lIT 1999) directions respectively
(a) 243 nm (b) 972 nm (b) rotation of the electron in anticlockwise and clockwise
(c) 486 nm (d) 182 nm directions respectively
93 207. The energy of the electron in the flISt orbit of He+ is (c) magnetic moment of electron pointing up and down
- 871.6 x 10-20 J..The energy of the election in the first orbit respectively
of hydrogen would be: (lIT 1998) (d) two quantum mechanical spin states which have no
(a) -871.6x 10-20 J (b) - 435 X 10-20 J classical analogues
20 20 104 218. Rutherford's experiment, which established the nuclear model
(c) -217.9x 10- J (d) -108.9x 10- J
of the atom, Osed a beam of: (lIT 2002)
94 208. The wavelength associated with a golf ball weighing 200 g and (a) j3.particles, which impinged on a metal foil and got
moving with a speed of 5 mIh is of the of: (lIT 2000) absorbed
(a) 10-10 m (b) 10-20 m (c) 10-30 m (d) 10-40 m (b) y·rays, which impinged on a metal foil and ejected
95 209. Who modified Bohr theory by introducing elliptical orbits for electrons
electron path? (CBSE 1999) (c) helium atoms, which impinged on a metal foil and got
(a) Hund (b) Thomson scattered . . >

(c) Rutherford (d) Sommerfeld (d) helium nuclei, which impinged on a metal foil and got
96 210. The uncertainty in momentum of an electron is 1 x 10-5 kg scattered
ms -1. The uncertainty in its position will be: 105219. How many moles of electrons weiflt one kilogram?
(h = 6.62 x 10-34 kg.m2 .s) (CBSE 1999; BHU 2010) (Mass of electron = 9.108 x 10- J kg, Avogadro's number
(a) 1.05 x 10-28 m (b) 1.05 x 10-26 m = 6.023 x 1023 ) (lIT 2002)
(c) 5.27x 10-30 m (d) 5.25 x 10-28 m (a) 6.023 x 1023 (b) _1_ X lerl
9.108
97 211. The Bohr orbit radius for the hydrogen atom (n = 1) is
approximately 0.530 A. The radius for the first excited state (c) 6.023 x 10S"4 (d) I x 108
9.108 9.108 x 6.023
(n = 2) orbits is: (CBSE 1998)
(a) 0.13 A (b) 1.06 A (c) 4.77 A (d) 2.12 A 106220. If the electronic configuration of nitrogen had ls 7, it would
have energy lower than that of the normal ground state
98 212. The number of nodal planes in px.orbital is: (lIT 2000)
configuration ls22i2p 3 because the electrons would be
(a) one . (b) two (c) three (d) zero
99 213. The angular momentum (L) of an electron in a Bohr orbit is closer to the nucleus. Yet ls7 is not observed because it
violates: (liT 2002)
given as: (lIT 1997)
 I

I 133
(a) Heisenberg uncertainty principle 116 230. In ground state, the radius of hydrogen atom is 0.53 A. The
(b) Hund's rule radius ofLi 2 + ion (Z =3) in the same state is: .
(c) Pauli's exclusion principle (PET (Raj.) 2007]
(d) Bohr postulates of stationary orbits (a) 0.17 A (b) 1.06 A (c) 0.53 A (d) 0.265 A .
117231. How many d-electrons in Cu + (At. No. = 29) can have the spin
107 221. The orbital angular momentum of an electron in 2s-orbital is:
(lIT 1996; AIEEE 2003; PMT (MP) 2004) quantum number (- f! (SCRA 2007)
I h (a) 3 (b) 7 (c) 5 (d) 9
(a)+-- (b) zero 118232. Which of the following electronic configurations, an atom has
22'1t
the lowest ionisation enthalpy? [CBSE (Med.) 2007)
h
(c)- (d)Ji !!.... (a) li2s 2 2p 3 (b) li2s'22p6 3s1
2'1t 2'1t
(c) ti2s 2 2p 6 (d) li2s 2 2p s
108 222. Calculate the wavelength (in nanometre) associated with a 119233. The measurement of the electron position is associated with an
proton moving at I x I (fl m sec -I.
uncertainty in momentum, which is equal to 1 x 10- 18 g cm s - I.
(mass of proton = 1. 67x 10-27 kg, h::::; 6.63 x 10-34 J sec)
The uncertainty in electron velocity is: (mass ofan electron is
(AIEEE 2009)
9 x 10- 28 g) ICBSE-PMT (Pre.) 2008]
(a) 0.032 nm (b) 0.40 nm
(a) Ix lOS ems- I (b) Ix lotI cms- I
(c) 2.5 nm (d) 14 nm
(c)lxI09 cms-' . (d)lxI0 6 cms- 1
-[1IiDt 120234. The ionization enthalpy of hydrogen atom is L312 x 1 0 ! J - - -
mol-I. The energy required to excite the electron in the atom
::::; 0.397x 10-9 m 0.4 nm] from n = 1 to n = 2 is : (AIEEE 2008)
109 223. The value of Planck's constant is 6.63 x 10-34 J-s. The (a) 9.84 x lOS J mol- I (b) 8.51 x lOS J mor l
velocity of light is 3 x I rf mI sec. Which value is closest to the (c) 6.56 x lOS J mol-I (d) 7.56 x lOS J mol- I
wavelength in nanometer of a quantum of light with frequency [Hint: El ::::; - I.312 X 106 J mol-'
of8x lotS sec-I? . (CBSE(PMT) 2003] E _EI _ 1.312xlO J 1- 1
6
...
18 2- 2 - - 4 mo
(a) 5 x 10- (b) 4 x 10' 2
(c) 3 X 107 (d) 2 x 10-25
110 224. Which of the following statements in relation to the hydrogen
t.E= (E2 - EI)::: 1.312 X 10 6

atom is correct? (AIEEE 2005) =

4
10
x 1.312 X 6 =9.84 x 105 J mol-']
(a) 3s-orbital is lower in energy than 3p-orbital
(b) 3p-orbital is lower in energy than 121235. The wavelengths of electron waves in two orbits is 3.: 5. The
ratio of kinetic energy of electrons will be: (EAMCET 2009)
(c) 3s--and 3p -orbitals are oflower energy than 3d-orbital
(a) 25: 9 (b) 5 : 3
(d) 3s, 3p -and 3d-orbitals all have the same energy
(c) 9:25 (d) 3:5
111 225. The number of d-electrons in Ni (At. No. ::: 28) is equal to that
of the: (CPMT (UP) 2004] [Hint: We know, A =
'I2Em
(a) sand p-electrons in F-
(b) p-electrons in Ar (At. No. = 18)
(c) d-electrons in Ni 2 + 1.2 vE;
(d) total number of electrons in N (At. No. = 1)
112 226. The number of radial nodes of 3s- and 2p-orbitals are 5
respectively: [lIT (Screening) 2005) .. E,:E2 =25:9]
(a) 2,0 (b) 0, 2 (c) 1,2 (d) 2, I 236. Electrons with a kinetic energy of 6. 023 x 104 l/mol are
113227. Which of the following is not permissible? (DCE 2005) evolved from the surface of a metal, when it is exposed to
(a) n = 4, 1= 3, m = 0 (b) n = 4, I = 2, m = 1 122 radiation of wavelength of 600 nm. The minimum amount of
=
(c) n 4, I = 4, m 1 = (d) n = 4, I = 0, m 0 =
114 228. According to Bohr theory, the angular momentum of electron energy required to remove an electron from the metal atom is :
d ,. . ••

in 5th orbit is: (AIEEE 2006) (a)· 2.3125x 10:Ci9

l (b) ,-' . , ...
h h h h
(a) 25- (b) 1- (c) 10- (d) 2.5- (c) 6.02x 10- 19
J (d) 6.62x 10- 34
J
'It 'It 'It 'It
115 [Hint: Absorbed energy = Threshold energy + kinetic energy
229. Which of the following sets of quantum numbers represents
the highest energy of an atom? (AIEEE 2007) of photoelectron
(a) n = 3, I = 0, m ::::; 0, S + = he
-r=Eo+KE
(b) n = 3, I = I, m = I, s = +
8 4
(c) n = 3, I = 2, m = I, s = + 6.62x 10-34 X 3 x 10 E. 6.023 x 10 JI
(d) n = 4, I::: 0, m = 0, s = + 600 x 10-9 = 0 + 6.023 X 1023
atom