Which one of the alkaline earth metals shows some anomalous behaviour and has the same electronegativity as aluminium?

Which of the following ions forms a hydroxide that is readily soluble in water?

Which element from the following exhibits a diagonal relationship with beryllium $(Be)$?

Which are the important ingredients present in Portland cement?

Which of the following is true for magnesium?

Choose the correct statements from the following:
$(I)$ In vapour phase $BeCl_2$ exists as a chlorobridged dimer.
$(II)$ $BeSO_4$ is readily soluble in water.
$(III)$ $BeO$ is completely basic in nature.
$(IV)$ $BeCO_3$ being unstable, is kept in an atmosphere of $CO_2$.
$(V)$ $BeCO_3$ is the least soluble among all the carbonates of group $2$ elements.