How did the physical models make it difficult to show what happens to the plates and mantle at plate boundaries?

neutrons are in the middle of the atom and the electrons, which are much smaller.

the right answer is c i just did the question.

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.