Gases exert pressure on containers because molecules __ with the walls of the
container.

The molecules are continually colliding with each other and with the walls of the container. When a molecule collides with the wall, they exert small force on the wall The pressure exerted by the gas is due to the sum of all these collision forces. The more particles that hit the walls, the higher the pressure. Hope this helped!

C. 1s22s22p63s23p43d104s24p5