Zn (Zinc) by itself has an oxidation state of zero since free elements have an oxidation state of zero (e.g. Na, Fe, H2, O2, S8). When bonded to other elements Zn has one main oxidation state: Zn 2+ .

For example, if Zinc is bonded Chlorine to form ZnCl2, since Cl is -1 (with a few exceptions) and there are two Cl atoms, the Zinc has an oxidation state of +2.

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RESOURCES
How to Find Oxidation Numbers (rules and examples): https://youtu.be/iSAwDJTLIKY
Oxidation Numbers Practice: https://youtu.be/hTjSNTOUcBQ

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GENERAL RULES
Free elements have an oxidation state of zero (e.g. Na, Fe, H2, O2, S8).
In an ion the all Oxidation numbers must add up to the charge on the ion.
In a neutral compound all Oxidation Numbers must add up to zero.
Group 1 = +1
Group 2 = +2
Hydrogen with Non-Metals = +1
Hydrogen with Metals (or Boron) = -1
Fluorine = -1
Oxygen = -2 (except in H2O2 or with Fluorine)
Group 17(7A) = -1 except with Oxygen and other halogens lower in the group
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