| A | B |
|---|
| compound | A substance made up of the atoms of two or more different elements. |
| periodic table | The table of elements in order of increasing atomic number, grouped by similar properties. |
| molecule | The grouping of two or more atoms joined together. |
| atom | The smallest unit of an element that has all the properties of thatelement. |
| element | The substance made up of only one kind of atom. |
| electron | The subatomic particle with a negative charge. |
| neutron | The subatomic particle with no charge. |
| proton | The subatomic particle with a positive charge. |
| nucleus | The center of an atom. |
