Nitrogen ($Z=7$) has the valence configuration $2s^{2}2p^3$.

• It has 5 valence electrons, so it commonly shows an oxidation state of $+5$.
• However, its maximum covalency (number of shared electron pairs) is only 4.
• Reason: Nitrogen belongs to the 2nd period and does NOT have vacant d-orbitals. It cannot expand its octet to accommodate more than 8 electrons.
• In ions like $N{H}_4^{+}$, it uses 3 covalent bonds and 1 coordinate bond, totaling 4 bonds.