| A | B |
| coordinate covalent bond | a bond in which one atom contributes both bonding electrons to a covalent bond |
| bond dissociation energy | the total energy required to break the bond between two covalently bonded atoms |
| bonding molecular orbital | a molecular orbital whose energy is lower than that of the atomic orbitals from which it is formed |
| sigma bond | molecular orbital that lies along the axis connecting two atomic nuclei |
| VESPR theory | states that because electron pairs repel, molecules adjust their shapes so that valence-electron pairs are as far apart as possible |
| hybridization | a process in which several atomic orbitals mix to form the same number of equivalent hybrid orbitals |
| polyatomic ion | a tightly bound group of atoms that behaves as a unit and carries a charge |
| van der Waals forces | a term that collectively refers to dispersion forces and dipole interactions |
| hydrogen bond | intermolecular attraction of hydrogen covalently bonded to a very electronegative atom also weakly bonds to an unshared pair of electrons of another electronegative atom |
| molecule | a tightly connected group of two or more atoms of nonmetallic elements that behave as an electrically neutral unit |
| bonding orbital | a molecular orbital that can be occupied by two electrons of a covalent bond |
| diatomic molecule | molecule consisting of two atoms |
| dipole | a.k.a. a polar molecule |
| dipole interactions | electrical attraction between oppositely charged regions of polar molecules |
| dispersion forces | weakest molecular interactions caused by the motion of electrons |
| single covalent bond | atoms joined together by sharing a pair of (2) electrons |
| double covalent bond | atoms joined together by sharing two pairs of (4) electrons |
| triple covalent bond | atoms joined together by sharing three pairs of (6) electrons |
| molecular compound | compound composed of a neutral group of atoms joined by covalent bonds |
| molecular formula | the chemical formula of a molecular compound |
| network solids | very stable substances in which all atoms are covalently bonded to each other |
| nonpolar covalent bond | atoms in a bond share the bonding electrons equally |
| pi bond | bonding electrons found in sausage-shaped regions above and below the bond axis of the bonding atoms |
| polar covalent bond | atoms in a bond share the bonding electrons unequally |
| polar molecule | molecule with a polar bond that causes one end of the molecule to be slightly negative and the other end slightly positive |
| resonance structure | occurs when it is possible to draw two or more valid electron dot structures for a molecule |
| structural formula | represents covalent bonds by dashes and shows the arrangement of covalently bonded atoms |
| tetrahedral angle | the 109.5° angle between the carbon and each hydrogen atom in a molecule of methane |
| unshared pair | pair of valence electrons that is not shared between atoms |