Number of protons that identify the atoms of an element
Atomic Mass
Mass of an atom of a particular element; average of the mass numbers of the naturally occurring isotopes of the element multiplied with their respective abundance
Mass Number
Sum of the number of protons and the number of neutrons
Isotopes
Atoms having the same number of protons but different number of neutrons, identified through their mass number
Ion
Atom or group of atoms that has positive or negative charge
