1. Chemical Bonding The Formation of Compounds

2. Lewis Theory The attraction between electrons of one atom to the nucleus of another atom contribute to what is known as chemical bonds. G.N. Lewis (1875-1946) recognized valence electrons bond from one atom to another electron transfer resulting in ionic bonds sharing electrons resulting in covalent bonds overlapping electrons resulting in metallic bonds

3. A. Why bonding? All atoms want a filled outer ring to be STABLE atoms (non-reactive)  Atoms bond to fill their outer electron ring  Stable=full set of valence electrons (electrons in the last ring)  Atoms that already have a filled outer ring are the noble gases  Bonding creates compounds like water H 2 O and glucose sugar C 6 H 22 O 11

4. B. Two Types of Bonding #1 Ionic CComplete transfer of electrons from one atom to another CCreates charged particles (called ions) OOpposite charges attract OOccurs between a metal and a non-metal atom GGives a compounds a high melting/boiling point

5. #2 Covalent Bonding  Atoms share electrons  Occurs between a non-metal and a non-metal atom

6. Properties of Covalent Bonds Low melting and boiling points Brittle solids

7. #3 Metallic Bonding -Electrons overlap -Occurs between two metal atoms -Gives metals their properties (malleability, ductility, conductivity)

8. Lewis Dot Structures Lewis structures show the valence electrons as dots arranged around the atomic symbol. hydrogen: sodium: chlorine: Na  H  Cl  

9. The Octet Rule Atoms tend to gain, lose, or share electrons until they have eight valence electrons.

10. Ionic and Molecular Compounds Formation of sodium chloride: Formation of hydrogen chloride: A metal and a nonmetal transfer electrons to form an ionic compound. Two nonmetals share electrons to form a molecular compound. Na  +  Na + [] Cl  Cl   H  + Cl    Cl  H

11. Learning Check Draw electron dot diagrams for: Hydrogen Carbon Nitrogen Oxygen These elements form life and make up cells, DNA, carbohydrates and proteins