The maximum number of covalent bonds formed by nitrogen is

Analyze the question: It asks for the maximum number of covalent bonds a nitrogen atom can form. The word "maximum" matters here.

Concept: Nitrogen has atomic number 7, so its electronic configuration is 1s² 2s² 2p³. It has 5 valence electrons and needs 3 more to complete its octet.

• Normally, it forms 3 covalent bonds by sharing its 3 unpaired electrons. Examples are NH₃ (ammonia) and N₂ (triple bond).
• Nitrogen also has a lone pair. It can donate this pair to an electron-deficient species and form a dative (coordinate) covalent bond. This gives a fourth bond.
• Example: NH₃ + H⁺ → NH₄⁺ (ammonium ion). Here nitrogen has 3 normal covalent bonds plus 1 dative covalent bond, so 4 bonds in total.

Why not more than 4? Nitrogen is in period 2, so it has no d-orbitals available. It can only use the 2s and 2p orbitals, which hold at most 8 electrons (4 pairs). That limits it to 4 bonds.

Solution:

• Normal covalent bonds: 3
• Dative bond from the lone pair: +1
• Maximum = 4

Answer: The maximum number of covalent bonds nitrogen can form is 4, which is option D.

Exam tip: If a question says "maximum" for nitrogen or oxygen, think of the dative bond. Nitrogen gives NH₄⁺ (4 bonds), and oxygen gives H₃O⁺ (3 bonds). If the question says "usual" or "normally", the answer for nitrogen is 3.