Relevant Concepts:

• subatomic particles

• cathode rays

• nuclear model 

• nucleus

• protons

• neutrons

• electrons

• atomic mass units

• mass number

• isotopes

• atomic weight

• mass spectrometer

• periodic table

• group

• diatomic molecules

• chemical formula

• empirical formula

• molecular formula

• ions

• cation

• anion

• chemical nomenclature