(a) Lithium, sodium, potassium are all metals that react with water to liberate hydrogen gas. Is there any similarity in the atoms of these elements? (b) Helium is an unreactive gas and neon is a gas of extremely low reactivity. What,. if anythin, do their atoms have in common?
(a) All these metals are highly reactive, they have same valence electrons i.e. 1 and can readily loose electrons to become positive ions. (b) Helium and neon have completely filled outermost shell.
