$Beryllium$ shows a diagonal relationship with:

The solubility in water of sulphates down the $Group \ 2$ ($Be$ group) is $Be > Mg > Ca > Sr > Ba$. This is due to

Write down the preparation,properties,and uses of Calcium sulphate $(CaSO_{4} \cdot \frac{1}{2} H_{2} O)$ (Plaster of Paris).

Given below are two statements: One is labelled as Assertion $A$ and the other is labelled as Reason $R$ :
Assertion $(A)$ : $BeCl_2$ and $MgCl_2$ produce characteristic flame.
Reason $(R)$ : The excitation energy is high in $BeCl_2$ and $MgCl_2$.
In the light of the above statements,choose the correct answer from the option given below :

Write the preparation,properties,and uses of calcium carbonate $(CaCO_3)$.

What are the products formed in sequence when excess of $CO_{2}$ is passed in slaked lime?