State True or False:
$(1)$ $90 \ g \ Na$ and $170 \ g \ K$ are present in a person with $70 \ kg$ of body weight.
$(2)$ Ionization enthalpy of alkaline earth metals increases on moving top to bottom.
$(3)$ In vapour phase,$BeCl_2$ possesses a polymer-like arrangement.
$(4)$ $CaCO_3$ is used in the preparation of mortar.

(A) $(1)$ True statement.
$(2)$ False statement: In a group,when moving top to bottom,atomic size increases and hence,ionization enthalpy decreases.
$(3)$ False statement: $BeCl_2$ possesses a polymer-like arrangement in the solid state,whereas it exists as a dimer or monomer in the vapour phase.
$(4)$ False statement: $Ca(OH)_2$ (slaked lime) is used to prepare mortar.