In 109, it is stated that there is a wide range of estimates given for the number of galaxies in the universe. Some put the number in the very low 100 billions, others bring it much closer to the one trillion mark.
The size of other galaxies range from one million to hundreds of billions of stars. The mass of some of the largest galaxies is trillions of times the mass of our sun. Again, it is supposed that much of this mass consists of dark and exotic matter.
If we consider our galaxy to be of average size, and use the highest estimates for both the number of atoms in our galaxy and the total number of galaxies, then the universe would contain about one trillion times the number of atoms as our galaxy. Since our galaxy probably has no more than 1069 atoms, this would mean that at most the universe contains 1069 x 1012 atoms in all. This works out to be just under 1081.
If we use lower estimates for the number of atoms in our galaxy and total number of galaxies, then the total number of atoms would be as much as 20 times less, or within the area of 1079.
Hence, "atoms in the universe" belongs on this page which spans from 1078 to just under 1081.