| A | B |
|---|
| atom | the simplest particle of an element that retains all of its properties. |
| atomic number | the number of protons in an atom |
| bond | attachements between atoms |
| chemical reaction | the rearrangement of atoms that cause the atoms to be more stable. |
| compound | a pure substance that is made up of atoms of two or more elements |
| covalent bond | when two atoms share one or more pair of electons |
| electron | small, negatively charged particles that orbit the nucleus of the atom |
| element | pure substances that cannot be broken down chemically. |
| energy level | the amount of energy that an electon has as it moves around the nucleus |
| ion | an atom or molecule with an electrical charge |
| ionic bond | the attraction between positive an negative charges formed when an electron is stolen |
| mass | the quantity of matter an object has. |
| matter | anything that occupys space and has mass |
| molecule | the simplest part of a substance that retains all of the properties of the substance and that can exist ins free state. |
| neutron | particle in the nucleus that has no charge |
| nucleus | the central core of an atom |
| proton | particle in the nucleus that has a positive charge |
