Who coined the term 'covalent bond'? And who explained the covalent bond using the electronic theory?

The electronic configuration of three elements $A$,$B$,and $C$ are given below. The bond between $B$ and $C$ will be:
$A: 1s^2, 2s^2, 2p^6$
$B: 1s^2, 2s^2, 2p^6, 3s^2, 3p^3$
$C: 1s^2, 2s^2, 2p^6, 3s^2, 3p^5$

Anhydrous $AlCl_3$ is used in the Friedel-Crafts reaction because it is

The total number of electrons that take part in forming bonds in $N_2$ is

Which of the following bonds requires the largest amount of bond energy to dissociate the atoms concerned?

The structure of aluminium bromide is best represented as :