Calculate the relative mass of Neon using this information. "Out of every 100 atoms, 90 are Ne-20, 1 is Ne-21 and 9 are Ne-22.

A reagent occasionally used in chemical synthesis is sodium-potassium alloy. One formulation of the alloy contains 68 atom percent ; that is, out of every 100 atoms, 68 are and 32 are . What is the mass percent of in this sodium-potassium alloy?

A compund of uranium and fluorine is used to generate uranium for nuclear power plants. The gas can be decomposed to yield 2.09 parts by mass of uranium for every 1 part by mass of fluorine. If the relative mass of a uranium atom is 238 and the relative mass of a fluorine atom is 19, calculate the number of fluorine atoms that are combined with one uranium atom.