The elements that apply are argon, neon and helium. These elements are called inert gasses and have unique properties that make them unreactive. These elements are so unreactive that they are classified as chemically inert. The elements belong to a group in the periodic table known as the Noble Gases. They belong to family 18 of the periodic table and have atoms with 8 valence electrons. This configuration causes the gases to be unreactive.
Because gravity treats all mass equally. It doesn't treat heavier objects with greater force. All objects experience the gravitational pull equally. Making the two different weights reach the ground together simultaneously despite their weight differences.
