Which element should not be kept in metal or glass bottles and why?The element can only be kept in wooden bottles.

Gallium is the element that should not be stored in metal
or glass containers. The reason is that gallium expands 3.1% when it solidifies at low
temperatures and this can cause the container to break open. In other words, gallium
expands when it freezes. For this reason, it is primarily stored in plastic packets
inside other containers.

Gallium, discovered by French
chemist, Paul Emile Lecoq de Boisbaudran, in 1875 has an atomic number of 31 and the
symbol Ga. It is in group 13 and is classified as a metal. Gallium becomes a liquid in
the range of room temperature and will actually melt if held in your bare
hand.