[nokia8650]

Hi

Is the magnitude of oxidation state of an atom the number of bonds which that atom forms?

Thanks

[pzona69]

That's not exactly right.  The oxidation state is the hypothetical charge that an atom would need to have to make all bonds to other atoms ionic. 
You can use the periodic table to find the common oxidation states of most elements (there is usually more than one possible state for each element).  Halogens are one group to the left of the Noble Gases, which gives them a common oxidation state of -1. The group to the left of halogens has a common oxidation state of -2, etc. This only works until you hit the d-block (the area in the middle of the table, lower than the rest). Most d-block elements have more than one common oxidation state.  The alkali metals (first group on the left) have common oxidation states of +1. The alkali earth metals are +2, etc. I'm sure there's someone else who can give a better explanation than that, but hopefully it was helpful.

http://en.wikipedia.org/wiki/Oxidation_state#Without_a_Lewis_structure

That link has some rules for finding oxidation states