| A | B |
|---|
| ionic bond | forms when one or more valence electrons is transferred from one atom to another, creating positive and negative ions. the "bond" is the attractive force between positive and negative ions |
| covalent bonding | involves sharing of valence electrons between atoms. |
| octet of electrons | regarded as stable configuration. Noble gases demonstrated little reactivity |
| isoelectronic species | molecules and ions having the same number of valence electrons and the same lewis sturctures |
| formal charge | the sum of this charge on atoms in a molecule or ion always equals the net charge on the molecule or ion. =group #-[LPE=1/2BE]. # assigned to each atom in the lewis structure cmpd. that designates the "charge" the atom has if bonding electrons are shared equally. |
| resonance structures | use to represents bonding in a molecule or ion when a single Lewis structure fails to describe accurately the actual electronic structure. the alternative structures have identical patterns of bonding and equal energy. |
| coordinate covalent bond | if a bonding pair of electrons originates on one of the bonded atoms |
| free radicals | chemical species both atomic and molecular with an unpaired electron. Are quite reactive generally |
| electron pair geometry | is the geometry taken up by all the valence electron pairs around a central atom |
| molecular geometry | describes the arrangement in space of the central atom and the atoms directly attached to it |
| polar bond | the bond between the two atoms has a positve end and a negative end; has negative and positive poles |
| electronegativity, x | a measure of the ability of an atom in a molecule to attract electrons to itself |
| charge distribution | the way electrons are distributed in a molecule or ion |
| electroneutrality principle | electrons will be distributed in such a way that charges on all atoms are as close to zero as possible |
| bond length | the distance between the nuclei of two bonded atoms |
| bond dissociation enthalpy | the enthalpy change for breaking a bond in a molecule with teh reactants and products in the gas phase |
| resonance | a blending of lewis structures into a single composite hybrid structure. >1 lewis structure |
| bond order | # of bonding electron pairs between 2 atoms. when is resonance is fractional. =sum of all bonds between single pair of atoms/#resonance structures |
| bond energy | energy or enthalpy (constant p) required to BREAK a chemical bond . |
