Ch. 1 Sec. 3 Ch. 1 Sec. 3

ion•atom or group of atoms that has an electric charge

• Much like people, most atoms don't like to live solitary existences.

• They need to COME TOGETHER with other atoms to lead more stable, happier lives.

• This process of coming together is called chemical bonding.

ionic bond

• forms a neutral ionic compound

• the 2 atoms then become oppositely charged ions & feel a strong electric attraction for each other

• formed between 2 atoms of a molecule when 1 atom transfers valence electrons to the other

Ionic bonding:Ionic bonding: In the playground at recess, a 3rd grader has a chocolate bar. A 7th grader takes the chocolate bar from the 3rd grader and the 3rd grader follows the 7th grader around for the rest of the recess, trying to get some of it back.

This is like a BIG Cl atom taking a little Li’s electron to make LiCl.

The animation shows the process that takes place during the formation of an ionic bond.

http://www.wisc-online.com/objects/index_tj.asp?objid=GCH2204

One electron is transferred from the sodium atom to the chlorine atom.

After losing an electron, the sodium atom becomes a sodium ion with a 1+ charge.

After gaining an electron, the chlorine becomes a chloride ion with a 1- charge.

[02:18]

1+

3+2+

4+ or 4-

3- 2- 1-

polyatomic ionspolyatomic ions

• ions that are made of more than 1 atomions that are made of more than 1 atom

Naming ionic compounds1. Name of positive ion (usually a metal)

2. Name of negative ion– if negative ion is an element- end of

its name changes to –ide– if negative ion is polyatomic- name

remains unchanged – example: Sodium

Bicarbonate

NaHCO3

Characteristic properties of ionic compounds:

1.1. crystal shapecrystal shape

[00:54]

2. high melting pointigh melting point

3. electrical conductivity

Bonding Basics- Ionic Bonds• Complete each ionic bond by using Froot

Loops. Use markers or crayons to draw the bonds.

1. Potassium + Fluorine

2. Magnesium + Iodine

3. Sodium + Oxygen

4. Sodium + Chlorine

5. Calcium + Chlorine

Characteristic Characteristic properties of ionic properties of ionic

compounds:compounds:

1.1.crystal shapecrystal shape

2. high melting point2. high melting point

3. electrical conductivity3. electrical conductivity

polyatomic ions

• ions that are made of more than 1 atom

sodium chloride

NaCl

How are ionic compounds named?1. Name of positive ion (usually a metal)

2. Name of negative ion– if negative ion is an element- end of

its name changes to –ide– if negative ion is polyatomic- name

remains unchanged – example:

sodium bicarbonate

NaHCO3

YouTube video-Based on song from Grease