Why does barium and iodine form bal2

Which of the following statements is not true? • a. covalent compounds have low melting and boiling points. • ob. covalent bonds between atoms of a compound are relatively weak compared to bonds between molecules. • c. covalent bonds occur between nonmetals. • d. covalent compounds are often gases or liquids.

Which function is performed by earths atmosphere? a. ultraviolet rays are prevented from reaching the ozone layer. b. earths temperature is raised and moderated by trapping in heat c. charged particles from the sun are prevented from reaching earth. d. magnetic charges from space are prevented from reaching earths surface.

Which characteristics can be used to differentiate star systems? check all that apply.