1. Chemical Bonding

2. Chemical Bonding
chemical bond - force holding atoms together in a compound or molecule.
Atoms form bonds to gain stability.
A “stable” atom has ______ valence electrons (octet rule). Exemptions: H & He (2) and B
Atoms will gain, lose, or share electrons to achieve a full octet.

3. Chemical Bonding Bonded atoms form compounds
Chemists use chemical formulas to represent the combination of elements that make up a compound.
Examples: NaCl, H2O, C6H12O6
Electron Dot Diagrams can be used to represent how bonding works

4. Chemical Bonding Three types of bonding: ionic, covalent, and metallic
Type depends on what types of elements are being bonded:
Metal to metal – metallic
Metal to nonmetal – ionic
Nonmetal to nonmetal – covalent

5. Ionic bonding
Ionic bonds occur due to a transfer of electrons between atoms
Ions result from ionic bonding – cations (+, same name as element) and anions (-, element name with suffix “-ide”)
Ionic bonds form ionic compounds
The chemical formula for compounds give the simplest ratio of the cations and anions
Examples: NaCl, MgBr2, CaO, Mg3N2

6. Ionic Bonding
Electron Dot Diagrams Br Na Cl Mg Br

7. Covalent Bonding
Covalent bonds occur as a result of a sharing of electrons between atoms
Since the atoms are sharing the electrons, no ions are formed
Covalent bonds form molecular compounds (molecules)

8. Covalent Bonding
Atoms can share more than one pair resulting, so covalent bonds can be single, double, triple or quadruple bonds
Chemical formula of molecular compounds gives actual structure of molecule
Examples: H2O, CO2, NH3

9. Covalent Bonding
Electron Dot Diagrams H O O C O H

10. Metallic Bonding
Metallic bonding results from nuclei of metal atoms existing in an area of free-flowing, delocalized electrons (often called a “sea of electrons”)

11. Metallic Bonding
The sea of electrons produce some of the properties of metals
Conduction of electricity (electrons can flow)
Malleability
Ductile
Alloy – mixture of metals
Alloys often have superior properties to those of the metals that make them up