In the following equation there are 100 g Na and 150 g of Fe2)3. Based on these measurements which of the following are true, 6Na+Fe2O3 = 3Na2O+2Fe

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.