$Lithium$,$sodium$,and $potassium$ are all metals that react with water to liberate hydrogen gas. Is there any similarity in the atoms of these elements?

(N/A) Yes. The atoms of all three elements—$lithium$,$sodium$,and $potassium$—have one electron in their outermost shells. This similarity in their electronic configuration (all belong to Group $1$) is the reason they exhibit similar chemical properties,such as reacting with water to release hydrogen gas.