| A proton and a neutron have about the same ____ (1 amu). |
anion |
| A group of atoms held together by covalent bonds is a ____. |
atom |
| The basic unit of an element is an ____. |
cation |
| A positively charged ion is called a ____. |
compound |
| Any atom or molecule that has a charge is an ____. |
electron |
| A negatively charged ion is called an ____. |
ion |
| An ____ is subatomic particle with a negative charge. |
mass |
| A ____ contains atoms of at least two different elements. |
molecule |
