Identify the $CORRECT$ decreasing order of melting point of cluster of sodium atoms depending on size.

Among the hydroxides and carbonates of $IA$ and $IIA$ group elements respectively,on moving down the group,the correct solubility order is:

Based on lattice energy and other considerations,which one of the following alkali metal chlorides is expected to have the highest melting point?

Which elements of group $1$ and $2$ differ from the other elements of the same group? Give a brief explanation of the diagonal relationship.

Ions of an element of group $1$ participate in the transmission of nerve signals and transport of sugars and amino acids into cells. This element imparts yellow colour to the flame in flame test and forms an oxide and a peroxide with oxygen. Identify the element and write chemical reaction to show the formation of its peroxide. Why does the element impart colour to the flame?

The order of negative standard electrode potential values $(E^\circ_{M^+/M})$ for $Li$,$Na$,and $K$ is: