Chemical Bonding

Molecule

a COVALENTLY bonded substance; can be atoms of the same element (Ex: diatomic elements/molecules); molecular substance = covalent substance

Compound

 a substance composed of two or more atoms from different elements CHEMICALLY bonded together

Bond

forces of attraction that hold atoms together in a molecule or compound

Octet Rule

atoms bond together in order to have 8 electrons in their valence shell

Exothermic

energy is RELEASED as a product of a chemical reaction

Endothermic

energy is CONSUMED as a product of a chemical reaction

Ionic Bond

chemical bond involving the TRANSFER of electrons between a metal and nonmetal atom (metals lose, nonmetals gain); electronegativity difference between elements typically GREATER than 1.7

Covalent Bond

chemical bond involving the SHARING of electrons between two nonmetal atoms; electronegativity difference between elements typically LESS than 1.7

Oxidation number

the “charge” an element has within a compound

Polyatomic ions

atoms of two or more elements chemically bonded together and having a NET CHARGE

Lone pair

A pair of valence electrons in an atom that are not shared with another atom in a covalent bond

Polar molecule

 a covalent molecule with an unequal sharing of electrons; contains atoms of two different nonmetal elements (all covalent compounds that are NOT diatoms)

Nonpolar molecules

a molecule with symmetrical/equal sharing of electrons

Intermolecular forces (IMF’s)

weak forces between molecules that hold the molecules to one another; not actually chemical bonds