Oxidation State/Number in General

[Jasmine 2C]

I understand that the oxidation number/state is the charge of an element. But what I don't understand is how certain elements can have so many different oxidation numbers, i.e. carbon, while others have so less, i.e. oxygen and hydrogen?
For example, homework problem 6K1 "The following redox reaction is used in acidic solution in the Breathalyzer test to determine the level of alcohol in blood: H+ (aq) + (Cr2O7)^2- (aq) + C2H5OH(aq) -> Cr3+ (aq) + C2H4O(aq) + H2O(l)
Identify the elements undergoing oxidation or reduction and indicate their initial and final oxidation numbers. (b) Write and balance the oxidation half-reaction. (c) Write and balance the reduction half-reaction. (d) Combine the half-reactions to produce a balanced redox equation.
Like just looking at the periodic table, I would assume the oxidation charge of carbon to either be 4+ or 4- in its most stable form, but then in this problem, carbon is oxidized from 2- to 1-.

[dtolentino1E]

i'm pretty sure this has to do with the electronegativity of the element, because some elements in compounds are more likely to attract electrons and have more stable/consistent oxidation states, while something like cardon can be a little more flexible.

[Rida Ismail 2E]

I think it depends on the energy of the element. Like in some cases there are different levels of energy lost by the electron, so it can become possibly semi-stable when it loses just 1 or 2 electrons. This way there are the oxidation states of -1 and -2. I'm not completely sure though.