Front

Smallest unit of an element with protons, neutrons, and electrons.

Back

Atom

Front

Mass of an atom or molecule; sum of protons and neutrons.

Back

Atomic Mass

Front

Number of protons in an atom's nucleus, equal to electrons in neutral atoms.

Back

Atomic Number

Front

Irreversible change of one substance into another, creating a new substance. Example: burning wood turns to ashes, which cannot revert to wood.

Back

Chemical Change

Front

Property of a substance during a chemical change (e.g., toxicity, oxidation, flammability). Iron oxidizes to rust.

Back

Chemical Property

Front

Number before a chemical formula indicating molecules in a reaction.

Back

Coefficient

Front

A substance of 2+ elements joined by chemical bonds in a definite ratio. Example: H2O (2 H, 1 O).

Back

Compound

Front

Mass per unit volume; how tightly packed an object is.

Back

Density

Front

Subatomic particle with a negative charge.

Back

Electron

Front

A substance that cannot be broken down by chemical means; all atoms are the same.

Back

Element