1. Oxidation And
Reduction

2. Oxidation
Process in which atoms or ions attain a more + oxidation state
Ex.
Na → Na+ + e
Cl- → Cl + e
Ca+ → Ca e

3. Reduction
Atoms or ions of elements attain a more negative oxidation state
Ex.
Cl + e → Cl-
Mnemonic: “OIL RIG”
Oxidation involves loss, reduction involves gain

4. Oxidation Number Uncombined elements have oxidation # of 0
Monoatomic ions have oxidation # equal to their ion charge
F is always –1 in a compound
O is almost always –2 in a compound
H is +1 in all compounds except those with metals (then its –1)
More electronegative element is assigned a number equal to its ion charge
Algebraic sum of oxidation numbers in a compound is always zero

5. Practice
Determine the oxidation numbers for each element in the compounds below
NaCl
H2SO4
AgNO3
CO2
SF6
NO3-