The correct answer is answer choice C. +1. Since electrons have negative charges, losing one electron will cause the atom to have a positive charge of 1. This charge comes from the protons, which, until one electron was lost, balanced out the negative charge of the electrons and caused the atom to be neutral.
Answer:
(a) 
(b) 
(c) 
Explanation:
(a) The orbital period is the time that the electron spend to travel the orbit of the atom. Thus, it is given by the length of the circular orbit divided by its velocity:

(b) Current means charge over time, So, in this case is charge over period:

(c) Magnetic moment is given by:

Here A is the area of the orbit.

Most of the momentum is transferred to the ball on top. Since the collision in this situation is elastic, momentum is conserved, meaning the momentum of both balls before hitting the floor is equal to the momentum of both balls right after the collision.