text: please tell me if these are oxifation or reductive half equations? please explain why briefly:  1) k = k+ + e- 2) h2 = 2h+ + 2e- 3)o = o2- - 2e- 4) cu+ = cu2+  + e- these are all oxidation half-reactions.  2 ways of determining this:  1)  if electrons are being listed as a product, you have oxidation. 2)  all of your reactants are going up in oxidation number.  example is k going to k+  (0 --> +1)