1. Bonding and Chemical Equations

2. Valance Electrons Electrons in the outer most orbit of an atom.
Available for elements to combine with other elements to create molecules and compounds.
Group 1 = 1 valance electron
Can share or donate this electron easily.
Group 2 = 2 valance electrons
Can share or donate these electrons.

3. Valence Electrons Group 16 = 6 valance electrons
Can accept 2 electrons.
Group 17 = 7 valance electrons
Can accept 1 electron.

4. Valance Electrons

5. Nobel Gases Group 18 – Nobel Gases
Outer orbit is completely filled with electrons.
Elements are happiest or stable when their outer orbits are completely full!
DO NOT bond with any other element to create molecules or compounds!

6. Bonding
An element’s goal is to reach the stable level, a full outer orbit.
To do this they bond with other elements based on how many electrons are needed to become stable.
Group 1
1 Valence electron – looking to bond with an element needing 1 or 2 electrons:
Group 16 – needs 2
Group 17 – needs 1

7. Bonding Group 1 & Group 17 H:F = Hydrogen Fluoride
Na:Cl = Sodium Chloride
Li:F = Lithium Fluoride

8. Bonding Group 1 & Group 16 H:O:H = Water Li:S:Li = Lithium Sulfide
Na:O:Na = Sodium Oxide
Na:O:H = Sodium Hydroxide

9. Bonding Group 2 & Group 16 Be:O = Beryllium Oxide
Mg:S = Magnesium Sulfide

10. Counting Atoms
Allows you to see the number of each element involved in a reaction.
All reactants must be present in the product in the same quantities!

11. Counting Atoms
Identify how many atoms of each element are present in each molecule or compound.
Calcium Carbonate - CaCO3
Calcium (Ca) -
Carbon (C) -
Oxygen (O) -
Magnesium Hydroxide – Mg(OH)2
Magnesium (Mg) -
Oxygen (O) –
Hydrogen (H) - 1 1 3 1
1 X 2 = 2
1 X 2 = 2

12. Chemical Equations
The Law of Conservation of Mass states that matter can’t be created or destroyed.
What you have present in the reactants of an equations MUST be present in the products.
Chemical equations must have equal numbers of atoms on the left of the equation (reactants) as it does the right (products).
H2 + O = H2O
__Mg + O2 = __MgO 2 2

13. Chemical Equations __P + __O2 = P4O10 N2 + __H2 = __NH3
Balance the following equations:
__P + __O2 = P4O10
N2 + __H2 = __NH3
__ Al + __ O2 = Al2O3 4 5 3 2 4 3

14. Chemical Equations Zn + O2 = ZnO P4 + H2 = PH3 H2O2 = H2O + O2 2 2 6 4
Balance the following equations:
Zn O2 = ZnO
P H2 = PH3
H2O2 = H2O O2 2 2 6 4 2