Atom Note Cards

Atoms: Building blocks of matter

Atomic Number: number of protons in an atom

Mass Number: number of protons and neutrons in the nucleus of an atom

Proton: positively charged subatomic particle found in the nucleus of
an atom.

Neutron: neutral subatomic particle found in the nucleus of an atom.

Electron: negatively charged subatomic particle found on energy
levels outside the nucleus of an atom.

Valance Electrons: The electrons found on the outermost energy level
of an atom. Their number determines how an atom
will bond or not bond with other atoms.

Nucleus: the center of the atom which makes up the mass of the atom.

Neutral Atom: An atom that has an equal number of protons and electrons,
therefore it has no charge.

Ion: An atom that has an unequal number of protons and electrons,
therefore it has a charge.
An atom becomes an ion by either losing or gaining electrons.

Isotope: An atom that has the same number of protons, but different numbers
of neutrons. Isotopes have the same atomic number but different
atomic masses.