An element has an atomic number of $56$. To which of the following does it belong?

As the alkaline earth metals (except $Be$) tend to lose their valence electrons readily,they act as:

Which of the following hydroxides is insoluble in water?

The element that does $NOT$ form an acidic oxide is

Which one of the alkaline earth metal carbonates is thermally the most stable?
$MgCO_{3}, CaCO_{3}, SrCO_{3}, BaCO_{3}$

Observe the following compounds.
$(i)$ $CaCO_3$
$(ii)$ $MgSO_4$
$(iii)$ $BaCl_2$
$(iv)$ $Sr(NO_3)_2$
$(v)$ $MgBr_2$
$(vi)$ $MgCl_2$
The oxoacid salts of group $II$ elements from the above list are