The oxidation states of phosphorus vary from

What is the oxidation state of gallium?

What is the oxidation state of sulfur in cyclic sulfur trioxide $(S_3O_9)$?

Using Stock notation,represent the following compounds: $HAuCl_{4}$,$Tl_{2}O$,$FeO$,$Fe_{2}O_{3}$,$CuI$,$CuO$,$MnO$,and $MnO_{2}$.

What will be the formula of the compound formed between the following elements?
$(i)$ The element with atomic number $19$ and iodine.
$(ii)$ The first element and oxygen.

Two elements $X$ and $Y$ have the following electronic configurations: $X = 1s^2, 2s^2 2p^6, 3s^2 3p^6, 4s^2$ and $Y = 1s^2, 2s^2 2p^6, 3s^2 3p^5$. The expected compound formed by the combination of $X$ and $Y$ is: