What are the three ions and/or molecules found in pure water?

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.

Based on its chemical properties, identify the position of each chemical family on the periodic table.

Which of the following units is not an official si unit