chemical-bonding

# Chemical Bonding Atoms bond to achieve lower energy states. The type of bond — ionic, covalent, or metallic — depends on the electronegativity difference and metallic character of the atoms involved. Once bonds form, the three-dimensional arrangement of atoms determines molecular shape, polarity, and physical properties. This skill covers bond formation, Lewis structures, VSEPR geometry prediction, hybridization, and the intermolecular forces that govern bulk behavior. **Agent affinity:** pauling (bonding/molecular chemistry, primary) **Concept IDs:** chem-ionic-bonding, chem-covalent-bonding, chem-molecular-geometry, chem-intermolecular-forces ## Bond Type Classification | Bond type | Electronegativity difference | Electron behavior | Example | |---|---|---|---| | Nonpolar covalent | < 0.4 | Shared equally | H-H, Cl-Cl | | Polar covalent | 0.4 - 1.7 | Shared unequally | H-Cl, O-H | | Ionic | > 1.7 | Transferred | NaCl, MgO | | Metallic | Between metals | Delocalized "sea" | Fe, Cu, Al | These boundaries are guidelines, not sharp cutoffs. Bond character exists on a continuum. ## Ionic Bonding **Mechanism.** Metal atoms lose electrons to form cations; nonmetal atoms gain electrons to form anions. The electrostatic attraction between oppositely charged ions forms the ionic bond. **Lattice energy.** The energy released when gaseous ions assemble into a crystal lattice. Higher lattice energy means a more stable compound. Lattice energy increases with higher ion charges...