Ionic bonds form between metal and nonmetal atoms when electrons are transferred. Positively charged metal ions are called cations, and negatively charged nonmetal ions are called anions. Ionic bonds occur when cations and anions are attracted to each other due to their opposite charges, balancing out the overall charge. Ionic compounds write their chemical formulas to represent this charge balance between the ions.

1. Ionic Bonds

2. Ionic Bonds
• An ion is an atom with a positive
or negative charge.
• Ions form by atoms gaining or
losing an electron.
– They become positive when they lose
one or more electrons
– They become negative when they
gain one or more electrons.

3. Ionic Bonds
• Ionic bonds occur between metals
and non metals.
– Metals form positive ions
– Nonmetals form negative ions.

4. Ionic Bonds
• Positive ions are called cations
• Negative ions are called anions
• Cations have lost electrons and
anions have gained electrons.

5. Ionic Bonds
• Because opposites attract, when
ions form, they bond to one
another due to magnetic
attraction.
– EX: Na (sodium) needs to lose one
electron to become stable, Cl
(chlorine) needs to gain one electron
to become stable. Na becomes
positive, Cl becomes negative and
they bond due to their opposite
charges.

6. Ionic Bonds
• Writing the formula:
– When ionic compounds form, they
balance out the charges of the ions.
The formula must represent this
balance.

7. Ionic Bonds
• Writing the formula:
– 2 Chloride ions (-1) will balance out
the charge of a Magnesium ion (+2).
– We write this formula out:
MgCl2
– The subscript 2 tells us that we have
2 Chlorine atoms. If no subscript is
written that means there is only one
atom.

8. Ionic Bonds
• How many atoms of each element
do I have in the following
formulas?
– Sodium Chloride: NaCl
– Calcium Carbonate: CaCO3
– Ammonium Nitrate: NH4NO3

9. Ionic Bonds
• Properties of ionic Compounds
– Hard and brittle solids with very high
melting points.
– When dissolved in water, they
conduct electrical currents.