In which of the following compounds is the octet complete $(C)$ or incomplete $(IC)$ for all atoms?
$Al_2Cl_6$ $-$ $Al_2(CH_3)_6$ $-$ $AlF_3$ $-$ Dimer of $BeCl_2$ $-$ Dimer of $BeH_2$
(Note: $C$ for complete octet and $IC$ for incomplete octet.)

Which of the following is not a Lewis acid?

Fill in the blanks given below:
$(i)$ The two theories based on the principles of quantum mechanics are ........ and ......... .
$(ii)$ The electronic configuration of carbon in the excited state is ........... .
$(iii)$ Through the combination of atomic orbitals,....... are formed.
$(iv)$ The ${\rm{CH}}_4$ molecule has a .......... shape.

Pick out the isoelectronic structures from the following:
$\mathop {CH_3^+}\limits_{I}$ $\mathop {H_3O^{+}}\limits_{II}$ $\mathop {NH_3}\limits_{III}$ $\mathop {CH_3^-}\limits_{IV}$

The pairs among $A = [SO_3^{2-}, CO_3^{2-}]$,$B = [O_2^{2-}, F_2]$,$C = [CN^-, CO]$,$D = [NH_3, H_3O^+]$ and $E = [MnO_4^{2-}, CrO_4^{2-}]$ that do not have similar Lewis dot structures are:

Given below are statements about some molecules/ions. Identify the $CORRECT$ statements.
$A$. The dipole moment value of $NF_3$ is higher than that of $NH_3$.
$B$. The dipole moment value of $BeH_2$ is zero.
$C$. The bond order of $O_2^{2-}$ and $F_2$ is same.
$D$. The formal charge on the central oxygen atom of ozone is $-1$.
$E$. In $NO_2$,all the three atoms satisfy the octet rule,hence it is very stable.
Choose the correct answer from the options given below: