| A | B |
|---|
| mass | A measure of the amount of matter in an object. |
| matter | Anything that has mass and takes up space. |
| weight | A measure of the force of gravity on an object. |
| nucleus | The central part of an atom. |
| neutron | A particle found in the nucleus of an atom. |
| proton | A particle found in the nucleus of an atom, with a positive charge. |
| electrons | Particles that move around the nucleus of an atom. |
| element | A substance made up of only one kind of atom. |
| orbits | The paths that electrons move in. |
| atom | The smallest particle of an element. |
| atomic number | The number of protons in the nucleus of an atom. |
| mass number | The total number of particles in the nucleus of an atom. |
| isotope | An atom of the same element that has a different number of neutrons. |
| periodic table | A chart containing many facts about elements and their atoms. |
| compound | A substance made up of two or more elements that are chemically joined. |
| molecule | A chemical unit made up of two or more atoms. |
| acid | A compound that contains hydrogen and that has a sour taste. |
| base | A compound that contains oxygen and hydrogen and that has a bitter taste and feels slippery. |
| indicator | A substance that changes color when it is added to an acid or a base. |
| neutral | The condition of a substance that is neither an acid or a base. |
| salt | A compound made from an acid and a base. |
| oxide | Compound formed when oxygen combines with another element. |
