Alkali metal - Group I elements
Alkaline earth metal - Group II elements
Anion - a negatively charged ion (negative ion)
Cation - a positively charged ion (positive ion)
Group - the vertical columns in the periodic table
Halogen - Group VII elements
Ion - formed when an atom either loses or gains one or more electrons and is either positively or negatively charged
Noble gas - a chemically inert gaseous element belonging to the same group (Group 0) as helium in the periodic table; noble gases in the air include argon, helium, neon, krypton and xenon
Octet rule - atoms become stable by having eight electrons in their outermost shells
Period - the horizontal rows in the periodic table
Periodic table - a table in which all chemical elements are arranged in order of increasing atomic number
Reactivity - how readily an element reacts with another element
Salt - a compound formed between a metal and a non-metal
Transition metal - elements between Groups II and III of the periodic table