1

NEET 2013

What is the maximum numbers of electrons that can be associated with the following set of quantum numbers ?
n = 3, $l$ = 1 and m = $-$ 1
A
4
B
2
C
10
D
6

Explanation

The orbitals associated with n = 3, l = 1 is 3p. One orbital (with m = -1) of 3p-subshell can only accomodate maximum 2 electrons.
2

AIPMT 2012 Mains

The orbital angular momentum of a p-electron is given as
A
${h \over {\sqrt 2 \pi }}$
B
$\sqrt 3 {h \over {2\pi }}$
C
$\sqrt {{3 \over 2}} {h \over \pi }$
D
$\sqrt 6 {h \over {2\pi }}$

Explanation

Orbital angular momentum (m) = $\sqrt {l(l + 1)} {h \over {2\pi }}$

For p-electrons; l = 1

Thus, m = $\sqrt {l(l + 1)} {h \over {2\pi }}$ = ${ \sqrt 2 {h}} \over 2 \pi$ = ${h \over {\sqrt 2 \pi }}$
3

AIPMT 2012 Prelims

The correct set of four quantum numbers for the valence electron of rubidium atom (Z = 37) is
A
5, 1, 1, + 1/2
B
6, 0, 0, +1/2
C
5, 0, 0, +1/2
D
5, 1, 0, +1/2

Explanation

Rb(37) = 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s1

For 5s, n= 5, l = 0, m = 0, s = +1/2 or -1/2
4

AIPMT 2012 Prelims

Maximum number of electrons in a subshell with $l$ = 3 and n = 4 is
A
14
B
16
C
10
D
12

Explanation

l = 3 and n = 4 represent 4f, So total number of electrons = 2(2$l$+1) = 14