What is the minimum mass of magnetite Fe3O4, a iron ore, from which 7.5kg of pure iron could be extracted? Be sure your answer has a unit symbol, if necessary, and is rounded to the correct number of significant digits.

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.