An ion from a given element has 20 protons and 18 electrons. What is the charge on the ion?
What is the name of the element?
What is the symbol for the ion?

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?