Question

an element shows variable valencies of 4 and 6 write the formula of its two oxides

Answer 1

If an element(M) shows variable valency of 4 and 6 then the formula of its two oxides will be :

$\stackrel{+4}{M}{\stackrel{-2}{O}}_2$ and $\stackrel{+6}{M}{\stackrel{-2}{O}}_3$