Oxidation numbers - OCR Chemistry A

What's the oxidation state of iron in Fe(s)?

What's the ox. no. of iron in Fe³⁺?

What's the ox no. of iron in FeCl₂?

What's the ox no. of iron in K₂FeO₄?

What's the ox no. of Cl in ClO^-?

What's the oxidation number of Cl in HClO₃?

What's the oxidation number of nitrogen in NO₂^-?

What's the oxidation number of hydrogen in H₂O₂?

What's the oxidation state of oxygen in H₂O₂?

What is the oxidation state of sodium in Na(s)?