Both $Be$ and $Al$ become passive on reaction with conc. nitric acid due to :

Assertion : Both $Be$ and $Al$ can form complexes such as $BeF_4^{2-}$ and $AlF_6^{3-}$ respectively,$BeF_6^{3-}$ is not formed.
Reason : In case of $Be$,no vacant $d-$ orbitals are present in its outermost shell.

Which of the following reactions does not take place?

An element of group $2$ forms a covalent oxide which is amphoteric in nature and dissolves in water to give an amphoteric hydroxide. Identify the element and write chemical reactions of the hydroxide of the element with an alkali and an acid.

State whether the following statements are True or False:
$(1)$ Plaster of Paris is used to join fractured bones and keep them immobilized.
$(2)$ Calcium carbonate and soil are the raw materials for cement production.

Calcium salts give which colour when put in a flame?