1. Bonding and Forces

2. Chemical Bonds What is a chemical bond?
An attraction between 2 or more atoms that allows us to create new substances
2 types of chemical bonds
Ionic
Covalent

3. Ionic Bonds
Ionic bond
A force that holds ions together in an ionic compound
One element takes electrons from another element
Can be broken easily by water
Form crystalline solids
Solids that have a pattern in which the ions are arranged

6. Covalent Bonds Covalent Bond
A physical bond made when 2 or more elements share electrons with each other
Each line drawn represents 2 electrons
H---H (the hydrogens are sharing 2 electrons)
Different amounts of lines represent different types of bonds
1 line
Sharing 2 electrons
A single bond
2 lines
Sharing 4 electrons
A double bond
3 lines
Sharing 6 electrons
A triple bond

8. Covalent Bonds 2 types of covalent bonds Polar covalent bonds
When the sharing of the electrons is unequal
Nonpolar covalent bonds
When the sharing of the electrons is equal

9. Polar Covalent Nonpolar Covalent
Examples
H2O
NH3 CO
Acids
HCl HI
HBr
Examples
N---N
F---F
H---H
O---C---O
CH4

10. How Do We Know What Bond Forms?
Based on electronegativity
The ability of an element to attract electrons when the atom is in a compound
The Rules of Predicting the Bonds
If the difference in electronegativity is 0-0.5
Nonpolar covalent
If the difference in electronegativity is
Polar covalent
If the difference in electronegativity is 1.6-higher
Ionic bond
In general
Increase from top to bottom in a group
Increase from left to right across a period

11. You Try
NaBr
CO2
NH3 HI
Cl2
C6H6
MgS

12. Forces and Bonding are Related
4 types of forces
London dispersion
Weakest force found in ALL compounds/molecules
ALWAYS PRESENT NO MATTER THE MOLECULE
Dipole-Dipole
Where a slight charge of a molecule is attracted to another slight charge of a different molecule
Present in polar covalent bonds that do not have Hydrogen with Fluorine, Oxygen, or Nitrogen
Hydrogen Bonding
Present in polar covalent bonds
Only when there is hydrogen with fluorine, oxygen, or nitrogen
Ionic Forces
Just ionic bonds

13. You Try
H2O
C2H6 HF
Cu2O
CH3F
CH3OH
Br2