| A | B |
| Atom | Basic unit of all matter |
| Electron | Tiny particle that travels around the nucleus of an atom |
| Proton | Particle in the nucleus of an atom |
| Element | Matter made up of only one kind of atom |
| Symbol | Short way of writing the name of an element |
| Mass | Amount of matter in an object |
| Carbon | An element that can be a black solid or a colorless crystal |
| Molecule | Simplest particle of many compounds |
| Indirect Evidence | Clues used to make guesses about things that cannot be seen |
| Matter | Anything that has mass and takes up space |
| Neutron | Particle in the nucleus of the atom |
| Nucleus | Central part of the atom |