Chemical Bonding & Molecular Structure

Main-group atoms tend to gain, lose, or share electrons to attain eight valence electrons, matching the stable noble-gas configuration (hydrogen seeks two).

An electrostatic attraction between oppositely charged ions, formed by transfer of electrons from a metal to a nonmetal. Example: Na⁺ and Cl⁻ in NaCl.

A bond formed by sharing one or more pairs of electrons between two nonmetal atoms, allowing both to approach a full octet.

Metal cations sit in a delocalized 'sea' of mobile valence electrons. This explains metals' conductivity, malleability, and luster.

Unequal electron sharing (electronegativity difference roughly 0.4–1.7) gives a polar covalent bond with partial charges; nearly equal sharing (difference under ~0.4) gives a nonpolar bond.

ΔEN ≈ 0–0.4: nonpolar covalent; ≈ 0.4–1.7: polar covalent; greater than ~1.7–2.0: ionic. The boundaries are approximate guidelines.