1

### AIPMT 2015

Which is the correct order of increasing energy of the listed orbitals in the atom of titanium ? (At. no. Z = 22)
A
4s 3s 3p 3d
B
3s 3p 3d 4s
C
3s 3p 4s 3d
D
3s 4s 3p 3d

## Explanation

Ti (22) $\Rightarrow$ 1s2 2s2 2p6 3s2 3p6 4s2 3d2

$\therefore$ Order of increasing energy is 3s, 3p, 4s, 3d
2

### AIPMT 2014

Be2+ is isoelectronic with which of the following ions ?
A
H+
B
Li+
C
Na+
D
Mg2+

## Explanation

Be2+ has 2 electrons and also Li+ has 2 electrons so Be2+ and Li+ are isoelectronic
3

### AIPMT 2014

Calculate the energy in joule corresponding to light of wavelength 45 nm. (Planck,s constant, h = 6.63 $\times$ 10$-$34 J s, speed of light, c = 3 $\times$ 108 m s$-$1)
A
6.67 $\times$ 1015
B
6.67 $\times$ 1011
C
4.42 $\times$ 10$-$15
D
4.42 $\times$ 10$-$18

## Explanation

E = $hc \over \lambda$

E = ${{6.63 \times {{10}^{ - 34}} \times 3 \times {{10}^8}} \over {45 \times {{10}^{ - 9}}}}$

= 4.42 $\times$ 10-18 J
4

### AIPMT 2014

What is the maximum number of orbitals that can be identified with the following quantum numbers ?
n = 3, l = 1, m1 = 0
A
1
B
2
C
3
D
4

## Explanation

Only one orbital 3p has following set of quantum numbers, n = 3, l = 1 and ml = 0