Which of the following pairs of atomic numbers represents elements belonging to the $s$-block?

What products are formed when $1 \ mol$ of calcium phosphide reacts with an excess of water?

What is the mixture of $MgCl_2$ and $MgO$ called?

Which of the following orders are correct?
$(I)$ Thermal stability: $BeSO_4 < MgSO_4 < CaSO_4 < SrSO_4$
$(II)$ Basic nature: $ZnO > BeO > MgO > CaO$
$(III)$ Solubility in water: $LiOH > NaOH > KOH > RbOH$
$(IV)$ Melting point: $NaCl > KCl > RbCl > CsCl > LiCl$

White vitriol is .......

Compare the alkali metals and alkaline earth metals with respect to $(i)$ ionization enthalpy,$(ii)$ basicity of oxides,and $(iii)$ solubility of hydroxides.