At what pressure does the mean free path of argon at 20 °c become comparable to the diameter of a 100 cm3 vessel that contains it? take σ = 0.36 nm2. sigma= collision cross section of argon.

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.

answerspecific gravity;

the correct answer would be b. amelia, because the particals of gas move really fast (charged particals) and gas also has a lot of room (particals move independently) so the only answer that has both of those is amelia's.