Ionic and Covalent Bonding Chapter 9

• Ions are charged particles formed when atoms gain or lose electrons.
• A chemical bond is a strong attractive force that exists between certain atoms in a substance.
• An ionic bond is a chemical bond formed by the electrostatic attraction between positive and negative ions.
• In a covalent bond, two atoms share valence electrons, which are attracted to the positively charged cores of both atoms, thus linking them.
• Salts are substances now known to be ionic. Salts are generally crystalline solids that melt at high temperatures.
• When large numbers of ions gather together, they form an ionic solid. The solid normally has a regular, crystalline structure that allows for the maximum attraction of ions, given their particular sizes.
• Lattice energy is the change in energy that occurs when an ionic solid is separated into isolated ions in the gas phase
• Two elements bond ionically if the ionization energy of one is sufficiently small and the electron affinity of the other is sufficiently large.
• The bonding between a metal and a nonmetal is ionic.
• Sublimation is the transformation of a solid to a gas.
• Bond order is the number of pairs of electrons in a bond.
• Bond Enthalpy is the average enthalpy change for the breaking of an A-B bond in a molecule in the gas phase.
• The negative sign means that heat is released by the reaction.