| A | B |
|---|
| atom | the fundamental of which elements are composed |
| matter | the material of the universe |
| element | a substance that cannot be decomposed into simpler substances by chemical or physical means. It consists of atoms all having the same atomic number |
| atomic number | the number of protons in the nucleus of a given atom |
| valence electrons | The electrons in the outermost energy level which are involved in bonding |
| Compound | a substance made of two or more elements joined together in a specific way |
| Nucleus | the tiny dense positively charged center of an atom |
| Proton | a positively charged subatomic particle in the nucleus of an atom |
| Electron | A negatively charged subatomic particle outside the nucleus of an atom |
| Metal | an element that gives up electrons relatively easily and is typically lustrous, malleable, and a good conductor of heat and electricity |
| Semimetal (metalloid) | an element that has both metallic and nonmetallic properties |
| Nonmetal | an element that does not exhibit metallic properties. Typically, a nonmetal accepts electrons from a metal |
| Atomic Mass | The total number of protons and neutrons in the nucleus of a given atom |
| Neutron | a subatomic particle which has no charge and is found in the nucleus |
| Isotopes | atoms with the same number of protons but different numbers of neutrons |
| First Ionization Energy | The amount of energy required to remove one electron from an atom |
| Electronegativity | The tendency of an atom in a molecule to attract shared electrons to itself |
