| A | B |
|---|
| Mass | A measure of the amount of matter in an object. |
| Matter | Anything that takes up space and has mass. |
| Weight | A Measure of the earth's pull of gravity on an object. |
| Nucleus | The central part of an atom |
| Protons | A positive particle found in the nucleus. |
| Neutrons | A neutral particle found in the nucleus |
| Orbits | The path of the electron around the nucleus. |
| Shell | The cirlce part of the atom that holds the electrons. |
| Elements | Matter made up of only one kind of atom. |
| Atom | The smallest part of an element. |
| Atomic Number | The number of protons in the nucleus. |
| Mass Number | The total number of particles in the nucleus |
| Electrons | The tiny negative particle that orbits around the nucleus in the shell of an atom. |
| Isotopes | An atom of the same element that has a different number of neutrons. |
| Periodic Table | Facts on elements and their atoms |
| 1118 | The number of known elements. |
