Use covalent Lewis structures to explain why the compound that forms between nitrogen and hydrogen has the formula NH3 and why NH2 and NH4 are not stable.

Covalent bonding occurs when two atoms share pairs of electrons to achieve a full outer shell, leading to greater stability. In the case of nitrogen and hydrogen, nitrogen has five valence electrons and needs three more to complete its octet, while each hydrogen atom has one electron. By sharing electrons, nitrogen can form three covalent bonds with three hydrogen atoms, resulting in the stable molecule NH3 (ammonia).

Lewis structures are diagrams that represent the bonding between atoms and the lone pairs of electrons in a molecule. They help visualize how atoms share electrons to form covalent bonds. For NH3, the Lewis structure shows nitrogen at the center with three hydrogen atoms bonded to it and one lone pair of electrons, indicating a stable arrangement. In contrast, NH2 (hydrazine) lacks a full octet for nitrogen, making it less stable.

The stability of ions and molecules is influenced by their electron configurations. NH4+ (ammonium) is stable because it has a full octet around nitrogen, but it carries a positive charge due to the extra hydrogen. NH2- (amide) is less stable because it has an incomplete octet and carries a negative charge, making it more reactive. Stability is often associated with achieving a full outer electron shell, which is not the case for NH2-.