Which of the following represents the correct order of solubility in water?

Which of the following compounds does not show amphoteric behaviour?

The alkaline earth metal that imparts apple green colour to the Bunsen flame when introduced in it in the form of its chloride is

Match the compounds in List-$I$ with their chemical formulas in List-$II$ and select the correct answer using the codes given below:
List-$I$ (Compounds) | List-$II$ (Formulas)
$(A)$ Plaster of Paris | $(i) \, CaSO_4 \cdot 2H_2O$
$(B)$ Epsomite | $(ii) \, CaSO_4 \cdot \frac{1}{2} H_2O$
$(C)$ Kieserite | $(iii) \, MgSO_4 \cdot 7H_2O$
$(D)$ Gypsum | $(iv) \, MgSO_4 \cdot H_2O$

What happens when:
$(i)$ Magnesium is burnt in air
$(ii)$ Quick lime is heated with silica
$(iii)$ Chlorine reacts with slaked lime
$(iv)$ Calcium nitrate is heated?

Alkaline earth metals are denser than alkali metals,because metallic bonding in alkaline earth metals is: