1.Element: a basic building block of matter; a pure substance that cannot be broken down into anything simpler.
2.Compound: a chemical combination of two or more elements into a single substance.
3.Atom: the smallest unit of an element that still has the properties of the element.
4.Proton: a particle with a positive charge in the nucleus of an atom.
5.Neutron: an uncharged particle in the nucleus of an atom.
6.Electron: a particle with a negative charge moving around the nucleus of an atom.
7. Nucleus: the dense center part of an atom.
8. Molecule: a group of more than one atom joined together that acts like a single particle.