COVALENT BONDS

Electrons are shared between 2 or more nonmetal atoms. Can also be between a nonmetal and a metalloid.

Ex: H2O, CO2, C6H12O6

EN value less than 1.5

All nonmetal atoms!

How Bonds Form

• Can be solid, liquid, or gas at room temp.• Low melting and boiling points

• Cannot conduct electricity• Insoluble in water• Polar Covalent bonds – electrons shared

unequally(EN difference 0.5 – 1.5)

• Nonpolar Covalent bonds – electrons shared equally

(EN difference 0 – 0.5)• Compounds are called “molecules”

Properties – think sugar!

Creates partial + and – ends

Lewis Dot StructuresOctet Rule: All atoms will form bonds in order to have full (8) valence electrons. Except Hydrogen (2)

1. Arrange element symbols so that first atom is in the middle.

2. Draw Lewis dot structures for each element.3. Circle electrons that will be shared between atoms.4. Re-draw atoms with lines as shared electrons.

Ex: CCl4

CCl

ClCl

Cl CCl

ClCl

Cl

Covalent Bonds between 2 elements can vary!

• 2 pairs shared = DOUBLE bond

• 3 pairs shared = TRIPLE bond

• 1 pair of valence electrons shared = SINGLE bond

Add in these examples under doc camera.H2ON2

NH3

HFCO2

Naming1. List the prefix and name of 1st element.

Don’t use “mono” on 1st element!2. Prefix and name of 2nd element + -ide ending.

Prefixes 1 =

mono2 = di3 = tri 4 = tetra5 =

penta

6 = hexa7 =

hepta8 = octa 9 = nona

10 = decaExamples CO2S2O3N4FCO Carbon

monoxide

Disulfur trioxideTetranitrogen monofluoride

Carbon dioxide

1. Write the symbol of the first element and subscript to match the prefix.

2. Repeat for 2nd element.DO NOT SIMPLIFY SUBSCRIPTS!Diatomic elements: H2 N2 O2 F2 Cl2 Br2 I2

Writing Chemical Formulas

Ex: Triphosphorus pentachlorideP3Cl5Ex: Tricarbon hexasulfideC3S6Ex: Antimony tetrabromideSbBr4

Lewis Dot Sharing Draw the Lewis Dot structures and show

the SHARING of unpaired electrons by circling. Then show the structural formula.

1. C2H4

2. CH4 5. CO2

3. N2 6. CCl4 8. F2

4. HCl 7. S2

Recap of Covalent Bonding!

Example:C2H4

Dicarbon tetrahydride

Example:C2O4

Dicarbon tetroxide

Example:Cl2O2

Dichlorine dioxide