So, they exhibit
similar chemical properties:
–They all react
with oxygen when exposed to air.
–They all react
with water to produce the hydroxide and hydrogen gas.
–They all react
with halogens to produce halides.
They exhibit a trend
in their reactivity:
–Reaction gets
more
vigorous going from
Lithium to Francium.
–In other
words, reactivity increases going down the group.
Why?
Before we answer that
questions, first why it is that elements react with each other in the first place.