a. Lithium, sodium, potassium are metals that react with water to liberate hydrogen. 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 anything, do their atoms have in common

These elements are alkali metals and they have 1 valence electron in their outermost shell and are therefore very unstable and reactive. b. These elements each have full outermost subshell, which results in high stability. They only react with other elements in extreme circumstances, the trait for which they are named.