Covalent bonds in ammonia (NH3)

Steps:

• Ammonia (NH3) has one nitrogen atom bonded to three hydrogen atoms.
• Each N-H bond is a single covalent bond sharing one pair of electrons.
• Nitrogen's valence electrons form three shared pairs with hydrogens.
• The lone pair on nitrogen is not shared.

Why A is correct:

• In NH3, three single N-H bonds each share one electron pair, totaling three shared pairs per Lewis structure rules.

Why the others are wrong:

• B: Includes nitrogen's unshared lone pair, which is not bonded.
• C: Overcounts by adding extra pairs not present in the structure.
• D: Confuses with total valence electrons or double bonds absent in NH3.

Final answer: A