CHEM 1110 Lecture Notes - Lecture 8: Formal Charge, Enthalpy, Electron Affinity

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Chem 1110: principles of chemistry 1 chapter 8 lecture notes. Metallic bonds: metal atoms bonded directly to several other atoms. Ionic bonds: electrostatic attraction between cations and anions. Covalent bonds: sharing of electrons in bonds between atomic centers. Bonding between atoms occurs: a) from overlap of atomic orbitals with shared electrons in them (covalent, b) from electrostatic attraction (ionic) Delocalized electrons not associated with an one nucleus. Usually solids resulting from metal and nonmetal bonds. Involves transfer of electrons from one atom tot the other. Attraction/bonding is primarily due to electrostatic forces between cations/ions with charges (q) Octet rule: atoms tend to gain, lose, or share electrons to acquire eight valence electrons: transition metals variable exceptions to octet rule. Properties of ionic compounds: hard, brittle, crystalline, high melting points, very negative heats of formation. Lattice energies: energy required to completely separate one mole of a solid ionic compound into its gaseous ions: lattice energies are always positive.