Oxidation, reduction and redox equations

What is oxidation?

It’s the loss of electrons, which causes an increase in the oxidation state.

What is reduction?

It’s the gain of electrons, which causes a decrease in oxidation state.

What is the reducing agent?

The substance that loses electrons and is oxidised.

What is the oxidising agent?

The substance that gains electrons and is reduced.

What is the oxidation state of elements such as O2, Na, Cl2?

0

What is the oxidation state of simple ions? For example, Na+ , Cl-

The charge on the ion.

Na+ = +1

Cl- = -1

What is the oxidation state of fluorine in compounds?

Always -1

What is the oxidation state of group 1 metals in compounds?

Always +1

What is the oxidation state of group 2 metals in compounds?

Always +2

What is the oxidation state of group 3 metals in compounds?

Always +3

What is the oxidation state of aluminium in compounds?

Always +3

What is the oxidation state of hydrogen?

Usually +1 but -1 in metal hydrides like NaH

What is the oxidation state of oxygen?

Usually -2 but -1 in peroxides like H2O2

In oxidation half equations what are the electrons?

The products

In reduction half equations, what are the electrons?

The reactants