Hydrogen, with one electron in its K shell, shares electrons with another hydrogen atom to form H₂. This sharing allows both hydrogen atoms to attain the electronic configuration of the nearest noble gas, helium.

A single covalent bond is formed when two atoms share a pair of valence electrons. This shared pair constitutes the bond, enabling both atoms to achieve a stable noble gas configuration in their outermost shells.

The electronic configuration of chlorine is 2, 8, 7. Its valency is 1, as chlorine requires one more electron to complete its outer shell.

In the electron dot structure of Cl₂, two chlorine atoms share one pair of electrons, forming a single covalent bond to achieve stable electronic configurations.

Nitrogen, with an atomic number of 7, forms a diatomic molecule (N₂) with a triple bond. Each nitrogen atom contributes three electrons, leading to three shared pairs, forming a triple bond in the electron dot structure of N₂.