<em><u>Element: A substance that is made up of only one type of atom. Compound: A substance that is made up of more than one type of atom bonded together. Mixture: A combination of two or more elements or compounds which have not reacted to bond together; each part in the mixture retains its own properties.</u></em>
Ionization energy is a measure of the difficulty involved in removing an electron from an atom or ion or the tendency of an atom or ion to surrender an electron.
