1. Structure -Elements

2. Structure: Elements
Elements: one type of atom Classification in the Periodic Table: Groups or Families: have similar characteristics Characteristics: Symbol: 2 letters: Capital and lower case Name: Atomic Number: # of protons Atomic Mass:# of protons + # of Neutrons Properties: metal, non-metal

3. Structure: Elements
Electron Shells: 2, 8, 8, 18 electron spaces (for our purposes) Drawing an atom Valance shell electrons: The electrons in the outer most shell. Generally these electrons are involved in bonding.

4. Structure: Elements
Isotopes: Have different versions of an element with different numbers of neutrons Atomic weight (revisited): Why a decimal number? Average weight of isotopes

5. Structure: Periodic Table
Columns: Groups or Families
Have the same number of valance shell electrons
Families can be referred to by name or number
Rows: periods
Increasing Atomic number

7. Structure: Groups/ Families
Hydrogen H: all by itself!
METALS (generally solids)
Alkali Metals (group 1): 1 valance electron, very reactive, never found alone
Alkaline Earth Metals (group 2): 2 valance electrons, fairly reactive, never found alone
Transition Metals (groups 3-12) : familiar metals, hard shiny, less reactive, versatile
Metalloids: (stair step) both metal and non metal properties
some conduct electricity some do not depending on temperature, used in semi -conductors in electronics

8. Structure: Groups/ Families
NON-METALS (generally gases )
Carbon Group: 4 valance electrons- can gain or loose electrons to complete valance shell
Nitrogen Group: 5 valance electrons,
Oxygen Group: 6 valance electrons
Halogen Group: 7 valance electrons, very reactive, salt forming, when alone very dangerous
Noble gases: full valance shell, very stable

9. Structure: Groups/ Families
RARE EARTH METALS/ SYNTHETIC
This group fits into the transition metals.
Lanthanides: rare metals, all very similar, soft malleable metals, used in alloys
Actinides: rare metals, radioactive, most are synthetic (man-made in particle accelerators)