| A | B |
|---|
| molecule | structure that results when atoms are joined together by covalent bonds |
| element | a pure substance that consists entirely of one type of atom |
| compound | substance formed by the chemical combination of two or more elements in definite proportions |
| ionic bond | formed when one or more electrons are transferred from one atom to another |
| ions | positively and negatively charged atoms |
| covalent bond | bond that involves sharing of electrons |
| atom | basic unit of matter |
| nucleus | protons and neutrons bound together form this at the center of the atom |
| electron | negatively charged particle that is in constant motion around the nucleus |
| isotopes | atoms of the same element that differ in the number of neutrons they contain |
| proton | positively charged particle in the atom |
| neutron | particle in atom that carries no charge |
