CHEMICAL BONDING

Chemical Bond

The attraction between atoms that holds them together and makes them function as a unit.

Ionic Bonds

Ionic Bonds An ionic bond is a transfer of

electrons between a metal and a nonmetal.

Electrons are completely transferred from one atom to another.

They either lose or gain electrons and form ions.

The atoms are bound together by the attraction between the opposite charges.

Types of Ions

The metal donates electrons and becomes positively charged-cation

The non metal gains electrons and becomes negatively charged-anion

Example

Writing Formulas1. Write the symbols of each element.2. Put their charge in their upper right corner.3. Crisscross the numbers down (Not the charges).

Example:Write the formula for Magnesium Chloride.

Mg Cl

Mg+2 Cl-1

Mg Cl

Writing Formulas PracticeWrite the formula for:

1. Aluminum Bromide

2. Calcium Oxide

3. Calcium Nitride

4. Sodium Chloride

1. Al Br

2. Ca O

3. Ca N

4. Na Cl

Covalent Bonds

Covalent Bonds A covalent bond is the sharing of

electrons between 2 nonmetals.

example

Both of the nonmetals want to gain electrons so they will share electrons to fill their orbitals. **A complete outer orbital has 8 electrons.**

Types of Covalent Bonds

Non-polar: an electron is shared equally between the atoms.Electronegativity difference: 0-0.3Ex: H2

Polar: an electron is more attracted to one atom than to another.Electronegativity difference: 0.3-1.7Ex: HCl

Electronegativity differences

Non-polar bond:

Ex: H2

2.1-2.1=0

Polar Bond:

Ex: HCl

3.0-2.1=0.9

Lewis Dot for Covalent Bonds

Can also be used to show bonding between atoms.

Electrons are placed between the atoms and are represented by a pair of dots or a dash.

Each dash represents one pair of electrons, or one bond.

H2O

The structural formula shows a shared pair of electrons by a dashed line.

Drawing Covalent Bonds

Example: CH4

Example: NH3

Multiple Bonds A single covalent bond is formed for every

pair of electrons shared between two atoms.

Some atoms can share multiple pairs of electrons, forming multiple covalent bonds. Single bond- 1 pair of electronsDouble bond- 2 pair of electronsTriple bond- 3 pair of electrons

example

Multiple Covalent Bonds Examples:

Oxygen has six valence electrons, so it needs two electrons to complete its octet.  When two oxygen atoms bond, they share two pairs of electrons, forming two covalent bonds. 

Extras Diatomic molecule- is a molecule

containing 2 identical atoms. Examples: H2 N2 O2 F2 Cl2 Br2 I2

Chemical Formula- represents the # of atoms of each element in a compound by using symbols and subscripts. Example: H2O H=2 O=1

Bonding Animation

Cartoon courtesy of NearingZero.net