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?

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

Yes, your assignment of oxidation states to the elements in the equation is correct. Let me explain how you can determine oxidation states in general.

Oxidation states (also known as oxidation numbers) are assigned to atoms in a chemical compound or equation to indicate the hypothetical charge that an atom would have if the compound was purely ionic. Here's how you can determine oxidation states:

1. For an atom in its elemental form, the oxidation state is always zero. In the case of diatomic oxygen gas (O2) in this equation, since it exists as O2 molecules, each oxygen atom is assigned an oxidation state of zero.

2. For monoatomic ions, the oxidation state is equal to the charge on the ion. In the reactant compound KClO2, the potassium ion (K+) has an oxidation state of +1 because it carries a single positive charge. The chloride ion (Cl-) has an oxidation state of -1 because it carries a single negative charge.

3. In neutral compounds, the sum of the oxidation states of all the atoms must equal zero. In the reactant compound KClO2, the sum of the oxidation states is: (+1) + (-2) + 2(X) = 0, where X is the oxidation state of oxygen in KClO2. By solving this equation, we find that the oxidation state of oxygen in KClO2 is +4.

4. In polyatomic ions, the sum of the oxidation states of all the atoms must equal the charge on the ion. In the product compound KCl, since it is neutral, the sum of the oxidation states is (+1) + (-1) = 0. Therefore, the oxidation states of both potassium and chloride in KCl remain the same as in the reactant compound.

Based on the determined oxidation states, you correctly identified that chlorine (Cl) is being reduced and oxygen (O) is being oxidized in this particular reaction. The chlorine changes its oxidation state from +1 to -1, which means it gains electrons and gets reduced. On the other hand, the oxygen changes its oxidation state from -2 to 0, indicating that it loses electrons and gets oxidized.