1. Bond

2. Ionic Bond
Unit 4: Ionic Compounds

3. Formation of Ionic Compounds
Ionic compounds are composed of cations (metals) and anions (nonmetals).
Although they are composed of ions, ionic compounds are electrically neutral. The positive charge equals the negative.
The positive charge and the negative charge attract one another. This is how the bond is formed.

4. Formula Units
Chemists represent the composition of substances by writing a chemical formula. A chemical formula shows the kinds and number of atoms in a substance.
Examples:
Sodium Chloride: NaCl
Copper Fluoride: CuF2

5. Formula Units
Ionic compounds exists as collection of negative and positive charge arranged in repeated patterns.
The chemical formula for an ionic compound, the formula unit, represents the smallest whole number ratio.
Examples: Magnesium Oxide: MgO
Magnesium Nitride: Mg3N2

6. Properties of Ionic Compounds
Most ionic compounds are crystalline solids at room temperature
Ionic compounds generally have high melting points.
Ionic Compounds can conduct electricity when melted or dissolved. This is because ionic compounds break down into their IONS when melted or dissolved in water.

7. Naming Binary Ionic Compounds
To name any binary ionic compound , place the cation first, followed by the anion name.
“Binary” just means that the compound has two elements in the formula.
The name of Cs2O, is cesium oxide.

8. Practice! LiF Name: 2. BaO Name: 3. BaCl2 Name: 4. K2O Name:
Lithium Flouride
Barium Oxide
Barium Chloride
Potassium Oxide

9. Drawing Electron Transfers
Draw the Lewis dot structure for each element:
Try Mg and Cl:
2. Use arrows to show how electrons move. Add more ions if needed.

10. 3. Write the formula by writing the number of ions used next to the symbol for each element. Formula: ___________________

11. 2 Ways to Write Ionic Compounds (Without drawing dot structures)
Write the element symbols with oxidation numbers: Try magnesium and chlorine
Add enough ions together so that the charges equal zero

12. 2 Ways to Write Ionic Compounds
3. Add up the ions and write the compound as a formula
4. Name:

13. 2 Ways to Write Ionic Compounds
Write the element symbols with oxidation numbers: Try magnesium and chlorine
Cross the numbers, not the signs

14. 2 Ways to Write Ionic Compounds
3. Reduce the ratio and drop any 1’s
4. Name: