Let the outermost electron number of Y be n, then the atomic numbers of W, X and Z are n, n- 1 and n+ 1 respectively, then there are n+n+n- 1+n+ 1=24, and n=6, then W is.

A, x, y and z become more nonmetallic. The stronger the nonmetal, the stronger the corresponding oxyacid with the highest valence, but it is not necessarily the highest valence in the options, so A is wrong.

B. nonmetal w (o) > x (p), the stronger the nonmetal element, the weaker the reducibility of the corresponding anion, so b is wrong;

C.x and y are in the same period, and the atomic radius x > y, so c is wrong;

The compound formed by D. O and hydrogen may be H _ H2O2 _ 2, which is nonpolar bond, so D is correct.

So choose D.