In the chemical compound magnesium chloride, MgCl2, one mole of magnesium chloride contains how many chloride ions?
A) 0.5 ions
B) 1.20 x 1024 ions
C) 3.01 x 1023 ions
D) 6.02 x 1023 ions

what are the choices?

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.