Atoms are extremely small.
The nucleus is the small, dense, positively charged center of the atom.
Proton a subatomic particle that has a positive charge and is found in the nucleus of an atom.
Neutron a subatomic particle that has no charge and that is found in the nucleus of an atom.
Atomic mass unit (amu) a unit of mass that describes the mass of an atom or molecule.
The volume of the nucleus is very small. So, the nucleus is very dense.
Electrons are subatomic negatively charged particles found outside of the nucleus of an atom.
Electrons are found within the electron cloud.