Question 1
A naturally occurring substance with a range of chemical composition is
◦ an element.
◦ a mineral.
◦ gangue.
◦ an ore.
◦ an amalgam.
Question 2
According to the band theory, a
band is
◦ an elastic force that holds electrons close to atoms in an insulator.
◦ the energy gap associated with semiconductors.
◦ a large number of molecular orbitals that are close together in energy.
◦ a large number of atoms in a crystal.