1. - Protons - positive charge - same mass as neutrons - Neutrons - no electrical charge - same mass as protons - Electrons - negative charge - very tiny mass - Nucleus - center of atom, with protons and neutrons - Energy Shells - orbits of electrons around the nucleus. Shell-like clouds of electrons.

2. Ions are atoms which lose or gain electrons due to unstable electron energy shells: - Cations - positively charged ions (too few electrons) - Anions - negatively charged ions (too many electrons) H : the hydrogen atom H+ : a positively charged hydrogen ion H- : a negatively charged hydrogen ion

3. covalent bonds: shared electrons (diamond, water) - ionic bonds: Bond formed from gaining or loosing an electron (NaCl).

4. Isotopes are atoms which lose or gain neutrons (change in mass, no change in charge). Hydrogen Atomic Mass = 1 Atomic Number = 1 Deuterium Atomic Mass = 2 Atomic Number = 1 Two isotopes of hydrogen

5. Number of Protons = Atomic Number = 36 Number of Electrons = Number of Protons = Atomic Number = 36 Number of Neutrons = Mass Number - Atomic Number = 84 - 36 = 48