Beside Metal: a headbanger's journey
Alkali metals are reactive because of their ionization energies. Ionization energy is the energy required to remove one electron from the atom. Alkali metals have only one valence electron, and if you'll recall all atoms want to be noble gases, i.e. they want full valence shells. Since alkali metals have this one electron in their valence shell, they'll readily give away their one electron than attempt to pull in seven electrons. Since alkali metals have such low ionization energies, and nature likes to use the least amount of energy possible for reactions, alkali metals tend to give up or share these electrons very, very easily. Hence, sodium explodes in water. :)
Do not wonder. alkali metals have only i electron in their outer shell, thus having an incomplete octet. If they lose an electron they achieve octet configuration. Thus they are very reactive. On reacting with water they form respective hydroxides.
The group 1 elements are the alkali metals. They have a valency of +1. Thus, they can easily lose that electron to gain the config. of the noble gases. They have very low ionization energy which makes losing the electrons all the more easier. Thus, they are highly reactive.
This Site Might Help You. RE: Why are Alkali Metals so reactive? Alkali Metals in the Periodic Table of Elements. Thanks!
Because alkali metals readily loose their outer shell solitary electron, they are highly reactive.
