Summarizing Types of Molecular Bonds

Summary

• Molecules form by two main types of bonds: the ionic bond and the covalent bond. An ionic bond transfers an electron from one atom to another, and a covalent bond shares the electrons.
• The energy change associated with ionic bonding depends on three main processes: the ionization of an electron from one atom, the acceptance of the electron by the second atom, and the Coulomb attraction of the resulting ions.
• Covalent bonds involve space-symmetric wave functions.
• Atoms use a linear combination of wave functions in bonding with other molecules (hybridization).

Glossary

covalent bond

bond formed by the sharing of one or more electrons between atoms

dissociation energy

amount of energy needed to break apart a molecule into atoms; also, total energy per ion pair to separate the crystal into isolated ions

electron affinity

energy associated with an accepted (bound) electron

equilibrium separation distance

distance between atoms in a molecule

exchange symmetry

how a total wave function changes under the exchange of two electrons

hybridization

change in the energy structure of an atom in which energetically favorable mixed states participate in bonding

ionic bond

bond formed by the Coulomb attraction of a positive and negative ions

Madelung constant

constant that depends on the geometry of a crystal used to determine the total potential energy of an ion in a crystal

polyatomic molecule

molecule formed of more than one atom

van der Waals bond

bond formed by the attraction of two electrically polarized molecules