All terms in this list:

Particle: A single, minute unit of matter

Atom: The smallest particle of an element that still retains the properties of that element

Compound: Form when two or more different types of atoms chemically combine

Molecule: Form when two or more atoms chemically combine

Nucleus: The center of the atom containing protons and neutrons

Proton: A positively charged particle in the nucleus of an atom

Neutron: An uncharged particle in the nucleus of an atom

Electron: A negatively charged particle orbiting the nucleus of an atom

Element Symbol: A one or two letter abbreviation representing an element; the first (or only) letter is always capitalized

Chemical Formula: A combination of number and letter abbreviations that represent chemical molecules or compounds

Coefficient: A number placed directly in front of a chemical formula declaring how many units of that molecule are present

Subscript: A number to the right of and slightly lower than an Element Symbol declaring how many atoms of that element are present

Variable: Anything in an experiment that could change during the course of the experiment

Independent Variable: The variable that is changed or manipulated on purpose during an experiment; it often “causes” the outcome of the experiment

Dependent Variable: The outcome that is observed or measured during an experiment; it is often called the “effect”

Constant Variable: Any variable that is kept the same during an experiment so it doesn’t interfere with the results