Which of the following is an example of a metallic crystalline solid?

Define the term 'amorphous'. Give a few examples of amorphous solids.

What type of solid is silica?

Enlist the characteristic properties of solid state.

$A$ group $14$ element is to be converted into $n-$type semiconductor by doping it with a suitable impurity. To which group should this impurity belong?

Choose the correct option for crystalline solids based on the following statements:
$(1)$ They do not have a sharp melting point.
$(2)$ They gradually soften upon heating.
$(3)$ They have an irregular three-dimensional arrangement.
$(4)$ They show a rapid change in volume upon heating.