a solution is prepared by mixing 360.0 mL of 0.25 M NaOH, 140.0 mL of 0.50 M NaOH, and 300.0 mL of distilled water. Assuming that the volumes are additive, the molarity of NaOH in the resulting solution is

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.