When lithium metal is burned in dry air, the product is a fine white
powder of lithium oxide, .
The 2:1 ratio of atoms is inevitable because each oxygen atom must
acquire two electrons to complete its neon shell, but each lithium
atom has only one outer electron to give. The powder actually is
made of microcrystals of
ions in a salt.
dissolves in water to produce hydrated
ions and hydroxide ions, so
is a basic oxide:
The important factor in this reaction is the oxide ion,
(see right). It has such a strong attraction for protons that it
can take one away from a water molecule, thereby creating two hydroxide
This reaction should remind you of the way that ammonia molecules
produce hydroxide ions by pulling water molecules apart: