The electronic configuration of $Cs$ is

$Al +$ aq. $NaOH$ (excess) $\longrightarrow P + Q$. $P$ and $Q$ are

Fill in the blanks:
$(1)$ ......... method is used to prepare sodium carbonate.
$(2)$ Sodium carbonate exists as .........
$(3)$ Sodium chloride is commonly known as .........
$(4)$ Sodium chloride melts at ......... temperature.

Which of the following is the chemical formula for dolomite?

Explain the significance of sodium,potassium,magnesium,and calcium in biological fluids.

$A$ metal $M$ on heating in nitrogen gas gives $Y$. $Y$ on treatment with $H_2O$ gives a colourless gas which when passed through $CuSO_4$ solution gives a blue colour. $Y$ is