19
MCQ (Single Correct Answer)
Which of the following statement is not correct from the view point of molecular orbital theory?
A
$\mathrm{Be}_2$ is not a stable molecule
B
$\mathrm{He}_2$ is not stable but $\mathrm{He}_2^{+}$is expected to exist.
C
Bond strength of $\mathrm{N}_2$ is maximum amongst the homonuclear diatomic molecules belonging to the second period.
D
The order of energies of molecular orbitals in $\mathrm{N}_2$ molecule is $\sigma 2 s<\sigma^* 2 s<\sigma 2 p_z<\left(\pi 2 p_x \simeq \pi 2 p_y\right)<\left(\pi^* 2 p_x \simeq \pi^* 2 p_y\right)<\sigma^* 2 p_z$
20
MCQ (Single Correct Answer)
Which of the following options represents the correct bond order?
A
$\mathrm{O}_2^{-}>\mathrm{O}_2>\mathrm{O}_2^{+}$
B
$\mathrm{O}_2^{-}<\mathrm{O}_2<\mathrm{O}_2^{+}$
C
$\mathrm{O}_2^{-}>\mathrm{O}_2<\mathrm{O}_2^{+}$
D
$\mathrm{O}_2^{-}<\mathrm{O}_2>\mathrm{O}_2^{+}$
21
MCQ (Single Correct Answer)
The electronic configuration of the outer most shell of the most electronegative elements is
A
$2 s^2 2 p^5$
B
$3 s^2 3 p^5$
C
$4 s^2 4 p^5$
D
$5 s^2 5 p^5$
22
MCQ (Single Correct Answer)
Amongst the following elements whose electronic configuration are given below, the one having the highest ionisation enthalpy is
A
$[\mathrm{Ne}] 35^2 3 p^1$
B
$[\mathrm{Ne}] 3 s^2 3 p^3$
C
$[\mathrm{Ne}] s^2 3 p^2$
D
$[\mathrm{Ar}] 3 d^{10} 4 s^2 4 p^3$
23
MCQ (Multiple Correct Answer)
Which of the following have identical bond order?
A
$\mathrm{CN}^{-}$
B
$\mathrm{NO}^{+}$
C
$\mathrm{O}_2^{-}$
D
$\mathrm{O}_2^{2-}$