CHEM 1411 Lecture Notes - Lecture 3: Trigonal Planar Molecular Geometry, Trigonal Pyramidal Molecular Geometry, Valence Bond Theory
Document Summary
Bonding theories explain how atoms bond together to form molecules. They explain why some combinations are stable and others are not. Bonds are formed when atoms obtain a stable electron configuration. Since the stable electron configuration is usually eight electrons in the outermost shell, this is known as the octet rule. Lattice energy is the energy associated with forming a crystalline lattice of alternating cations and anions from the gaseous ions. Since the cations are positively charged and the anions are negatively charged there is a lowering of potential energy. Lattice energy decreases (becomes less negative) as the atomic radius increases. Lattice energy increases (becomes more exothermic) with increasing charge. Electronegativity is the ability of an atom to attract electrons to itself in a chemical bond. Electronegativity generally increases across a period in the periodic table and decreases as you go down a column (group). In a pure covalent bond, two atoms of identical electronegativities share electrons equally.
