Presentation is loading. Please wait.

Presentation is loading. Please wait.

Forming New Substances

Similar presentations


Presentation on theme: "Forming New Substances"— Presentation transcript:

1 Forming New Substances
Chapter 9 - 2 Part 2

2 Writing Formulas - Ionic Compounds
The formula must have subscripts that cause the charges of the ions to cancel out making the compound neutral. An oxidation number is a positive or negative number.

3 Crisscross Method 1. Write the chemical symbols for each element in the compound (positive 1st) Ex: compound of calcium & chlorine Ca Cl 2. Write the oxidation numbers above the symbols Ca Cl 3. Crisscross the oxidation numbers making them subscripts. Ca Cl1- 4. Fill in the formula. CaCl2

4

5 Continued If they have the same charges or can be reduced, then they cancel each other out. For example: Li F = LiF Al 3+ P = Al3P3 or AlP Ca C = Ca4C2 or Ca2C Pb S = Pb2S4 or PbS2

6 Let’s Practice 1. Be N 2. Ca F 3. Sr P 4. Ba Pb 5. Al I 6. K O
7. Mg Br 8. Na Cl

7 NAMING THE FORMULAS Ionic compounds do not use prefixes like covalent compounds do. The second name ends in “ide” just like covalent do. Examples: Be3N2 Beryllium Nitride or CaF2 is Calcium Fluoride

8 LET’S TRY IT!


Download ppt "Forming New Substances"

Similar presentations


Ads by Google