Earth Science Ch. 3 Vocab

Front

Element

Back

A substance that cannot be broken down into simpler substances by physical or chemical means.

Front

Atom

Back

The smallest part of an element that can exist either alone or in combination.

Front

Nucleus

Back

The center of an atom.

Front

Proton

Back

A tiny particle in an atom that has mass and a positive charge.

Front

Neutron

Back

A particle in an atom with approximately the same mass as a proton but is electrically neutral.

Front

Atomic Number

Back

The number of protons in an atom’s nucleus.

Front

Electron

Back

A particle in an atom that has little mass but has a negative electric charge.

Front

Atomic Mass

Back

The sum of the protons and neutrons in an atom.

Front

Radioactivity

Back

The release of energy from the decay of the nuclei of certain kinds of atoms and isotopes.

Front

Molecule

Back

Combination of two or more atoms joined by covalent bonds.