1. Element
   1. atom
      1. smallest part of element
      2. behaves like the element
      3. unique
      4. sub-atomic particles
         1. NB relative scale.
         2. very little mass or charge
      5. M: Mass number
         1. P + N
      6. A: Atomic Number
         1. P
      7. E: Element
   2. isotope
      1. protons
         1. same number
      2. neutrons
         1. different numbers
      3. chemical properties
         1. same
      4. physical properties
         1. slightly different
2. Relative Atomic Mass
   1. Ar
   2. The average mass of a mole of atoms of an element on a scale where the mass of a carbon atom is 12 units
      1. average mass
      2. 1 mole
      3. element
      4. carbon 12 atom = 12 units
   3. moles = mass/Ar
   4. example
      1. chlorine 2 isotopes : 75% Chlorine 35, 25% Chlorine 37. Ar= 35.5
3. Electrons
   1. Configuration
      1. shells
         1. oxygen
            1. 8 electrons
            2. arrangement 2,6
         2. phosphorus
            1. 15 electrons
            2. arrangement 2,8,5
      2. chemcial properties
         1. group 1 elements
            1. outer shell
            2. 1 electron
            3. elements
            4. Lithium (2,1)
            5. Sodium (2,8,1)
            6. Potassium (2,8,8,1)
            7. properties
            8. highly reactive
            9. metals
         2. group 7 elements
            1. Halogens
            2. outer shell
            3. 7 electrons
            4. elements
            5. Flourine (2,7)
            6. Chlorine (2,8,7)
            7. Bromine (2,8,18,7)
            8. Iodine (2.8.18.18.7)
            9. properties
            10. highly reactive
            11. NON-metals
         3. group 8 elements
            1. Noble gases
            2. outer shell
            3. 8 electons
            4. filled
            5. elements
            6. helium (2)
            7. neon (2.8)
            8. argon (2.8.8)
            9. krypton (2.8.18.8)
            10. xenon (2.8.18.18.8)
            11. properties
            12. extremely stable
            13. unreactive
   2. Carbon Electronic Structure
4. Periodic Table
   1. arrangement
      1. chemical properties
      2. physical properties
      3. PERIODICITY
         1. number of electrons in outer shell
         2. increase to right, between periods