Where are non-metals located on the periodic table on the right of the periodic table after the staircase where would you find the most metallic element at the bottom left of the periodic table?

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?