What element in the periodic table of elements has the greatest number of electrons

Francium is the element with the greatest amount of electrons

Mary concludes that the foam rubber balls’ acceleration during the collision was THE SAME AS the steel balls’ acceleration. She concludes that the collision between the foam rubber balls is an ELASTIC collision.

The masses of the two objects are the same therefore its acceleration would also become the same. It is an elastic collision because little or less friction occurred in the situation creating kinetic energy.