17
MCQ (Single Correct Answer)
$$\begin{array}{llllll} A & 1 s^2 & 2 s^2 & 2 p^6 & & \\ B & 1 s^2 & 2 s^2 & 2 p^6 & 3 s^2 & 3 p^3 \\ C & 1 s^2 & 2 s^2 & 2 p^6 & 3 s^2 & 3 p^5 \end{array}$$
The bond between $B$ and $C$ will be
A
ionic
B
covalent
C
hydrogen
D
coordinate
18
MCQ (Single Correct Answer)
Which of the following order of energies of molecular orbitals of $\mathrm{N}_2$ is correct?
A
$\left(\pi 2 p_y\right)<\left(\sigma 2 p_z\right)<\left(\pi^* 2 p_x\right) \approx\left(\pi^* 2 p_y\right)$
B
$\left(\pi 2 p_y\right)>\left(\sigma 2 p_z\right)>\left(\pi^* 2 p_x\right) \approx\left(\pi^* 2 p_y\right)$
C
$\left(\pi 2 p_y\right)<\left(\sigma 2 p_z\right)<\left(\pi^* 2 p_x\right) \approx\left(\pi^* 2 p_y\right)$
D
$\left(\pi 2 p_y\right)>\left(\sigma 2 p_z\right)<\left(\pi^* 2 p_x\right) \approx\left(\pi^* 2 p_y\right)$
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
$5 s^2 5 p^5$