Explain the physical characteristics of group $13$ elements.

(N/A) Boron is non-metallic in nature. It is an extremely hard and black-coloured solid.
It exists in many allotropic forms. Due to its very strong crystalline lattice,boron has an unusually high melting point.
The rest of the members are soft metals with low melting points and high electrical conductivity.
It is worthwhile to note that gallium,with an unusually low melting point $(303 \ K)$,can exist in a liquid state during summer.
Its high boiling point $(2676 \ K)$ makes it a useful material for measuring high temperatures.
The density of the elements increases down the group from boron to thallium.