1. Bonding
4-4

2. Valence Electrons
Elements are arranged in the periodic table in groups
Atoms properties are determined by the outer number of electrons in the cloud
Valence electrons

4. Bonding Bonded atoms usually have a stable electron configuration
Valence electrons interact
Structure similar to noble gases

5. Bonds
Bonds can be stretched without breaking
Flexible rubber bands

6. Metals and Non-Metals

7. Ionic Bonds
Ionic Bond – formed by attraction between oppositely charged ions
Formed between:
Metal Elements – positive
Nonmetal Elements - negative

9. Ionic Bonds Formed by the transfer of electrons
Instead of sharing outer most electrons they are transferred
Na+ ion and Cl- ion

10. Ionic Compounds Na+ and Cl- form to make NaCl
1:1 Ratio for a zero charge
Ca2+ and F- form to make CaF2
1:2 Ratio for a zero charge

11. Ionic Compounds
When melted or dissolved in water ionic compounds conduct electricity
Electric current – moving charges
Melting points very high

12. Covalent Bond
Covalent Bond – formed when atoms share one or more pairs of electrons
Compounds made of molecules
Water and sugar
Nonmetal with nonmetal

13. Covalent Bond
Most of the molecules remain intact and do not conduct electricity
No charge
Low melting point