The diagram shows four different locations in an atom. the diagram has 3 shaded shapes with 2 and 3 in the middle and 4 at the bottom. it also contains a 1 in the circle surrounding the shaded shapes. which locations are likely to have subatomic particles with the least mass? a. 1 and 2.
b. 2 and 3.
c. 1 and 4.
d. 3 and 4.

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.