5) For 1 atom of Lithium-6, I will need atoms of Lithium-7 for an average atomic mass of 6.944. Switch to the slider button instead of the bowl so that you can select more than 10 atoms to verify your prediction. Set Lithium-6 to 1. Then move the slider until the average is close to 6.944. Record what the actual number needed.

answer: atomic mass was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.

explanation:

originally atomic mass was used to arrange elements on the periodic table from left to right in a row. each column then shows similar properties of elements of a group.

in modern periodic table, the atoms are arranged in increasing atomic number. as atomic number represents the number of protons in an atom which is unique for every atom.