why are elements on the periodic table not arranged by mass?
Here’s the picture for the answers.

Answer:
A. Similar elements have such different masses that this would lead to a completely random arrangement of elements.
Explanation:
Because it is the number of protons, which is identical to the atomic number, that separates different elements from each other, not the atomic mass.
Answer:
This would not allow all of the elements with similar properties to be lined up with each other.
Explanation: