Name the three allotropes of carbon.

The electronic configuration of an element $\mathrm{A}$ is $2, 6$. Is it likely to form:

$\mathrm{A}:$ a diatomic molecule $\left({\mathrm{A}}_2\right)$

$\mathrm{B}:$ a triatomic molecule $\left({\mathrm{A}}_3\right)$

$\mathrm{C}:$ a tetra-atomic molecule $\left({\mathrm{A}}_4\right)$

(Enter your correct answer as $\mathrm{A}, \mathrm{B} \mathrm{or} \mathrm{C}$)

Draw Lewis structure for ${\mathrm{H}}_2$.

Draw Lewis structures for ${\mathrm{Cl}}_2$.

Draw Lewis structures for ${\mathrm{CO}}_2$.

Write the electronic configurations of $\mathrm{C}$ and $\mathrm{H}$ atoms, and then calculate the total number of valence electrons in ${\mathrm{CH}}_4$.