2. A 0.45g sample of mineral ore is analyzed for chromium and found to contain 0.560mg Cr2O3. Express the concentration of Cr2O3 in the sample as: (a) Percent (%) (b) Parts per thousand (ppt) (c) Parts per million (ppm) (d) Parts per billion (p

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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.