Question

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

Answer 1

Yes. The atoms of all the three elements lithium, sodium, and potassium have one electron in their outermost shells.

Answer 2

 Lithium, sodium and potassium are all metals which belong to group 1, and have 1 valence electron in their atoms. They all have the same electronic configuration. Therefore, each element shows similar chemical properties when reacting with water and liberates hydrogen gas.