1. How Elements Form Compounds
Ionic and Covalent Bonds

2. Compound
Two or more elements chemically combined.

3. Ionic Compounds
called an ionic compound because it is made up of negative and positive ions that have resulted from the transfer of electrons from a metal to a non- metal.

4. Ionic Compounds
Ions in ionic compounds are held together by the electrostatic force between oppositely charged bodies. In other words, positive and negative ions attract.

5. Ionic Compounds For example:
Sodium (Na) wants to lose ____ electron). Chlorine (Cl) wants to gain ____ electron).

6. Ionic Compounds

7. Ionic Compounds

8. Calcium Fluoride
Calcium needs to lose ____ electrons, and fluorine needs to gain ____

9. Calcium Fluoride
What happens?

10. Calcium Fluoride
What happens?

11. Chemical Formulas and Composition of Compounds
In the chemical formula the symbols of elements are written with a subscript which indicates how many of that element are present in the compound
only numbers above one are written

12. Chemical Formulas and Composition of Compounds
Formula for sodium chloride =
Formula for calcium fluoride =
NaCl
CaF2

13. Ionic compounds are called electrolytes.
Electrolytes are substances that when dissolved in water, conduct electricity.
Electrolytes

14. Covalent/Molecular Compounds
form when non-metals combine with non-metals
non-electrolytes because they form solutions that do NOT conduct electricity.

15. Covalent/Molecular Compounds
Valence electrons are shared between atoms to fill the outer shell