Calcium fluoride, CaF2, is an example of ________. A) an ionic ...

[itsmyluck]

Calcium fluoride, CaF2, is an example of ________.
 
  A) an ionic compound
  B) a metallic compound
  C) a covalent compound
  D) a polar covalent compound

Question 2

How is it possible for an atom to emit visible light even though the atom is smaller than the wavelength of visible light?
 
  A) It's not possible. If a single atom emitted visible light, an atom would be visible under a high powered microscope.
  B) Any charged object, including the smallest atom, generates electromagnetic waves as it vibrates, which we observe in the visible spectrum of an element.
  C) As the electrons from an atom are excited, some of them reach escape velocity thus leaving the sphere of influence of the nucleus. These photons are observed in the visible spectrum.
  D) An atom does not emit light in the visible range of the spectrum, only in the UV wavelength range, since ultraviolet light wavelengths are smaller than atoms.

[nmyers]

Answer to Question 1

A

Answer to Question 2

B