Why do elements within a group have similar chemical properties?

Alidded glass container is filled with a colored gas. after a period of time, it is observed that the gas is uniformly spread throughout the box and that the movement has slowed considerably. next, a warm iron plate is carefully placed under the box. why is there resumed movement of the gas in the container?

0.88 moles of n2o5 (g) was placed in a sealed 1.00 l vessel. calculate the equilibrium concentration of n2o5. no2, and o2 and the equilibrium constant after equilibrium has been reached by 65.0% of the n2o5 decomposing.

This has nothing to do with school. i wrote a poem to my crush, who i'm asking out soon. tell me if it's cheesy, or cute. "roses are red, violets are blue no love story sounds right if it doesn't include you. dance with me all night, gaze into my eyes i'll hand you my heart, as well as my pride. when i hear your name, my heart goes insane. your all that i want, all that i need promise me you'll stay with me. here it is the final line, jasmine hill will you be mine? " i'm also going to buy her flowers, teddy bear and some food lol. written by me, bre (: