What is the realationship beetween atmospheric pressure and the density of the gas particles in an area of decreasing pressure

 As air pressure in an area increases, the density of the gas particles in that area increases.

(happy to help)

Explanation:

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.

answer:

technetium is the most reactive. this is followed by silver. the least reactive out of these three elements is strontium.