If you are referring to science, then you are correct. A period is also known as a family.
Answer:
Potential energy is energy that is stored – or conserved - in an object or substance. This stored energy is based on the position, arrangement or state of the object or substance. You can think of it as energy that has the 'potential' to do work.
Force, newtons 3rd law of motion stated for every action there is an equal and opposite reaction