Topic 3: Redox I

Question 1

Oxidation numbers

Answer 1

Tells you how many e- an atom has donated/accepted to form an ion
Uncombined and homonuclear elements have 0
For molecular ions it is equal to the overall charges

Question 2

Hydrogen

Answer 2

Oxidation state of +1
Except when bonded to metals then it is -1
Molecular hydrogen 0

Question 3

Oxygen

Answer 3

Oxidation state 2-
Except in peroxides it is -1
Molecular oxygen O2 has 0

Question 4

Redox reaction

Answer 4

Oxidation is loss of e-, reduction is gain
**to balance oxygen in ionic equations add water to the equation