If the electronic configuration of an element is $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^{6}3{\mathrm{d}}^{2}4{\mathrm{s}}^2$, the four electrons that participate in the chemical bond formation will be from :

The electronic configurations of the elements A, B, and C are given below.

$\mathrm{A}<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>1{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{p}}^6$
$\mathrm{B}<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>1{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{p}}^6<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>3{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>3{\mathrm{p}}^3$
$\mathrm{C}<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>1{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{p}}^6<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>3{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>3{\mathrm{p}}^5$

The stable form of A may be represented by the formula:

The electronic configurations of the elements A, B, and C are given below.

$\mathrm{A}<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>1{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{p}}^6$
$\mathrm{B}<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>1{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{p}}^6<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>3{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>3{\mathrm{p}}^3$
$\mathrm{C}<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>1{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{p}}^6<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>3{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>3{\mathrm{p}}^5$

The bond between B and C will be :