Can someone please help me with this? I would really appreciate it!

Question

Which rule concerning oxidation numbers is NOT true?

A. Fluorine always has an oxidation number of –1 in molecules that contain two or more types of atoms.

B. Oxygen has an oxidation number of –2 in molecules that contain two or more types of atoms.

C. If all else fails, assume that the atom’s oxidation number is the same as what it would take on in an ionic compound.

D. Reduction is the process by which an atom gains electrons.

E. Oxidation is the process by which an atom gains electrons.

Answer 1

Some of these choices are vague at best. For example, B. oxygen has an oxidation number of -2 in molecules that contain two or more types of atoms. Well, H2O2 contains 2 types of atoms but the oxidation number of oxygen is 1-, so this statement would NOT be true. Also, I'd take exception to C, which states "if all else fails, assume that an atom's oxidation number is the same as what it would take on in an ionic compound. While this is generally the case, not always would an ionic compound form, so one might consider this as false. Now, we know for sure that E. is NOT true, because oxidation is the process by which an atoms loses electrons, not gains electrons. So this is NOT true.

So, in summary, I think for sure that B and E are NOT true, but if I had to pick one choice only, I'd pick E because that for sure is not true.