Do elements in the s or p block generally have one common oxidation number?

Answer 1

No, this is not the case. Firstly, a simple substance (pure element) always has oxidation number 0. Then there is the fact that when combining with an element more electronegative than the element in question it will tend to have a positive oxidation number while if the element is more electropositive it will tend to have a negative oxidation number.

Nitrogen is a good example:

-3 in NH3

-2 in N2H4

-1 in NH2OH

0 in N2

+1 in N2O

+2 in NO

+3 in NaNO2

+4 in NO2

+5 in HNO3

Other elements are not as versatile as nitrogen, but a typical non-metal will show all odd or even oxidation numbers over a range of 8 units, as well as zero, while a typical metal will show all odd or even oxidation numbers between 0 and its valence.

The elements that do show only one common oxidation number (other than zero) are all of the s-block elements and fluorine and oxygen.