| A | B |
|---|
| atomic mass | average mass of protons & neutrons in an atom |
| periodic table | chart organizing the elements by # of protons |
| proton | positive charged particle in nucleus of atom |
| neutron | neutral charged particle in nucleus of atom |
| electron | negative charged particle moving around nucleus of atom |
| nucleus | core of atom containing protons & neutrons |
| atomic mass unit | a unit used to measure the mass of particles in atoms; a protron or neutron has a mass of 1 amu |
| atomic number | number of protons in the nucleus of an atom |
| chemical symbol | a one- or two- letter representation of an element |
| family | elements in the same vertical column of the periodic table; also called a group |
| group | elements in the same vertical column of the periodic table; also called a family |
| period | horizontal row of elements in the periodic table |
| valence electrons | one of the electrons farthest away from the nucleus of an atom; these electrons are involved in a chemical reaction. |
| neutral atom | number of protons and electrons are equal |
| coefficient | # in front of element telling # of molecules |
| subscript | #following an element telling # of atoms |
| chemical equation | describes a chemical reaction |
| chemical formula | tll how a compound is formed |
| conservation of matter | mass cannot be created or destroyed only rearranged |
| conservation of mass | the mass in the reactant equals the mass in the products |
