Which of the following are amphoteric oxides?

Fill in the blanks:
$(1)$ Calcium oxide is commonly known as .......
$(2)$ $A$ suspension of calcium hydroxide in water is known as ....
$(3)$ The common name of calcium hydroxide is .......
$(4)$ The general name of calcium sulphate hemihydrate is ......

Explain the physical properties of alkaline earth metals (Group $2$).

Which of the following has the lowest solubility?

What are methanides?

Alkaline earth metals (except $Be$) can easily lose their valence electrons. Therefore,how do they behave?