Nomenclature Definition List

Chemical nomenclature is concerned with naming chemical compounds and writing their formulas. Gathered below are definitions of several terms used in nomenclature. Amazingly enough, you need to know these definitions to learn chemical nomenclature!!

oxidation state

an alternate term that can be used when referring to the charge on an atom (but not a polyatomic ion.) There is a technical definition to this work, but it occurs later in the course. See the Redox section for more information.

metalloid

an element which has the capacity to act as either a metal or a nonmetal, depending on the chemical circumstances

nonmetal

an element that tends to gain electrons, becoming negatively charged; see anion

metal

an element that tends to lose electrons, becoming positively charged; see cation

ion

an atom or group of atoms with either a positive or a negative charge

cation

positively charged ion. Here is a picture of a cation:

anion

negatively charged ion. The phrase "anions are negative ions" might help you to remember.

monoatomic ion

a single atom ion (mono means one) Ex: Na⁺ or Cl¯

polyatomic ion

a many atom ion (poly means many) which acts chemically as one unit. Example: NO₃¯ (1 Nitrogen atom, 3 Oxygen atoms and an extra electron giving the ion a charge of 1¯. It does not have a 3¯ charge).

ionic compound

a compound containing at least one ionic bond (contains metal(s) & nonmetal(s))

covalent compound

a compound containing only covalent bonds (covalent compounds are really molecules; contains only nonmetal atoms)

binary ionic compound

ionic compound with only 2 kinds of atoms

binary molecular compound

covalent compound with only 2 kinds of atoms