Question

I'm a bit iffy on oxidation numbers... can someone please tell me if this is correct?

Assign oxidation states to each element on both sides of the equation : KClO2--->KCl+O2

Reactants
K = +1
Cl = +1
O = -2

Products
K = +1
Cl = -1
O = 0

the element being reduced is Cl and the element being oxidized is Oxygen... is that correct?

Answer 1

products ok.
reactants:
K is +1
O is -2 EACH for a total of -4.
Therefore, Cl must be +3 to make KClO2 zero.
K2Cr2O7
K is +1
Cr is +6 each
O is -2 each
Total + = (2*1) +(2*6) = 14
Total - = 7*-2 = -14