An electronic configuration representing an atom in the excited state is: 

$1.$ $1{\mathrm{s}}^2,2{\mathrm{s}}^{2}2{\mathrm{p}}^1$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$
$2.$ $1{\mathrm{s}}^2,2{\mathrm{s}}^{2}2{\mathrm{p}}^2$
$3.$ $1{\mathrm{s}}^2,2{\mathrm{s}}^{2}2{\mathrm{p}}^2,3{\mathrm{s}}^1$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$ $$
$4.$ $1{\mathrm{s}}^2,2{\mathrm{s}}^{2}2{\mathrm{p}}^5$

How does the energy gap between successive energy levels in an atom vary from low to high n values?

(1) All energy gaps are the same

(2) The energy gap decreases as  n increases

(3) The energy gap increases as  n  increases 

(4) The energy gap changes unpredictably as  n  increases

Iodine molecule dissociates into atoms after absorbing light of 4500 $\stackrel{\circ }{A}$. If one quantum of radiation is absorbed by each molecule, calculate the kinetic energy of iodine atoms. Bond energy of I₂ is 240 kJ mol^-1.

1. $2.16\times {10}^{-20} J$

2. $0.16\times {10}^{-20} J$

3. $5.03\times {10}^{-20} J$

4. $8.32\times {10}^{-20} J$

The orientation of an atomic orbital is governed by:

(1) azimuthal quantum number

(2) spin quantum number

(3) magnetic quantum number

(4) principal quantum number

Given: The mass of electron is 9.11 x 10^-31 kg

Planck constant is 6.626 x 10^-34 Js

the uncertainty involved in the measurement of velocity within a distance of 0.1 $\stackrel{°}{\mathrm{A}}$ is:

(a) 5.79 x 10⁶ ms^-1                      (b) 5.79 x 10⁷ ms^-1

(c) 5.79 x 10⁸ ms^-1                      (d) 5.79 x 10⁵ ms^-1

Which one of the following ions is the most stable in aqueous solution?

(1) Cr³⁺                         

(2) V³⁺

(3) Ti3+                         

(4) Mn³⁺

(At no. Ti=22, V=23, Cr=24, Mn=25)

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?

1. ii, iii and iv                             

2. i, ii, iii and iv

3. ii, iv and v                               

4. i and iii

The measurement of the electron position is associated with an uncertainty in momentum which is equal to 1x10^-18 g cm s^-1. The uncertainty in velocity of the electron will be:

(mass of an electron is 9 x 10^-28 g)

1. 1 x 10⁹ cm s^-1                     

2. 1 x 10⁶ cm s^-1

3. 1 x 10⁵ cm s^-1                     

4. 1 x 10¹¹ cm s^-1

If uncertainty in position and momentum are both equal, then uncertainty in velocity will be: 

1. $\frac{1}{2\mathrm{m}}\sqrt{\frac{\mathrm{h}}{\mathrm{\pi }}}$

2. $\sqrt{\frac{\mathrm{h}}{2\mathrm{\pi }}}$

3. $\frac{1}{\mathrm{m}}\sqrt{\frac{\mathrm{h}}{\mathrm{\pi }}}$

4. $\frac{\mathrm{h}}{\mathrm{\pi }}$

Which of the following is not permissible arrangement of electrons in an atom ?

1. n=4, l=0, m=0, s=-1/2

2. n=5, l=3, m=0, s=+1/2

3. n=3, l=2,m=-3, s=-1/2

4. n=3, l=2, m=-2, s=-1/2