1. Covalent Bonds
When Atoms Share

2. Atoms = smallest unit of a substance that still has all the properties of that substance
Element = substance that is made up of only one type of atom
Molecule = 2 or more atoms covalently bonded together
Carbon C O2
Oxygen
Carbon Dioxide, CO2

3. Chemical Bonds Attractive force that holds atoms or ions together
Two Types of Bonds
Ionic
Covalent

4. Covalent Bond
bond formed when atoms share one or more pairs of electrons.
covalent compounds can be solids, liquids, or gases.

5. Covalent Bonds occur between a nonmetal and a nonmetal
H2O = water
CO2 = carbon dioxide
CH4 = methane
NH3 = ammonia
HCl = hydrochloric acid

6. 3 Types of Covalent Bonds
Single Bond
2 electrons are shared between 2 atoms
Double Bond
4 electrons are shared between 2 atoms
Triple Bond
6 electrons are shared between 2 atoms

7. Cl Cl Cl Cl O O O O Cl – Cl Cl2 O = O O2
2 shared electrons = single covalent bond
Chlorine + Chlorine Cl Cl Cl Cl
Cl – Cl
Cl2
Oxygen + Oxygen O O O O
O = O O2
4 shared electrons = double covalent bond

8. H H O H O O + = = H H H Na + Cl [Na]+ [ Cl ]- + = [Na]+ [ Cl ]-
They are sharing the electrons = covalent bond
Hydrogen “thinks” it has 2 electrons so its happy
Oxygen “thinks” it has 8 electrons so its happy H H O H O O + = = H H H
2 hydrogen atoms
1 oxygen atom
1 water molecule
Chlorine takes an electron from sodium
Sodium is + and Chlorine is -
Opposite charges are attracted to each other = ionic bond
Chlorine has a full outer shell (8 electrons)
Sodium has a full outer shell (8 electrons) Na + Cl
[Na]+
[ Cl ]- + =
[Na]+
[ Cl ]-