What is the order of electrical conductivity in metals?

Classify each of the following solids as ionic,metallic,molecular,network (covalent) or amorphous.
$(i)$ Tetra phosphorus decoxide $(P_{4}O_{10})$ $(ii)$ Ammonium phosphate $(NH_{4})_{3}PO_{4}$
$(iii)$ $SiC$ $(iv)$ $I_{2}$ $(v)$ $P_{4}$ $(vi)$ Plastic $(vii)$ Graphite $(viii)$ Brass $(ix)$ $Rb$ $(x)$ $LiBr$ $(xi)$ $Si$

Crystals of which pair are isomorphous?

Under which situations can an amorphous substance change to crystalline form?

Which of the following elements has a simple cubic lattice structure in its solid state?

Solid $A$ is a very hard electrical insulator in solid as well as in molten state and melts at extremely high temperature. What type of solid is it?