Describe how the International Union of Pure and Applied Chemistry (IUPAC) changed the way in which groups of the periodic table are numbered.

the molecules move in straight line until they collide with each other or with the walls of the container. collisions are perfectly elastic; when two molecules collide, they change their directions and kinetic energies, but the total kinetic energy is conserved.

explanation:

because of all the things that happen around the us, many people get into arguments which sadly could get physical, but we should actually make a change for that.