Answer these questions, if u don’t know the answer to all just answer the first one

Imagine that someone pushes one marble toward a motionless marble. would there still be action-reaction forces involved in the collision? how might the marbles’ motions be changed? ?

Achlorine atom has 17 protons and 18 neutrons. what is its mass number? what is its atomic number?

The electric potential a distance r from a small charge is proportional to what power of the distance from the charge? a. r^-1 b. r c. r^-2 d. r^2