Which of the following occurs in an ionic bond?
a: oppositely charged ions attract.
b: two atoms share two electrons.
c: two atoms shares more than two electrons.
d: like-charged ions attract

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.