Which of the following is held together by dispersion and dipole- dipole forces?

 Which covalent network crystal is an exception in electrical conductivity? 

 Which crystal has mobile electrons that are free to move through out the crystal? 

 Which of the following has low melting points?

 Which type of solid is graphite? 

 In which crystal light is reflected from the surface?

As a rule, substances in the _________ state are denser than the other two states.

________ is a point within the crystal so that an imaginary straight line drawn through it will meet the surfaces of the crystal at equal distances on each side of the point.

In ________ there is a structural particles at the center of each face in addition to a structural particle at each corner of the unit cell.

___________ solids have distinct geometric shapes.