How is the variability in oxidation states of transition metals different from that of the non-transition metals? Illustrate with examples.

In transition metals, it can be observed that the oxidation state of the metal varies from +1 to +7 which is obtained by removing all its valence electrons. In transition elements the oxidation state differ by 1 unlike non transition elements whose oxidation state differs by 2, for example in transition metals (Cu2+,Cu3+ and Fe2+ ,Fe3+) and  In non-transition elements, this variation is selective, always differing by 2, e.g. S exhibits +2, +4, +6 oxidation states and N exhibits +3, + 5, etc.