Answer:
Electrons are in constant motion around the nucleus due to the electromagnetic force.
Option d is correct.
Step-by-step explanation:
The nucleus in the center of the atom is positively charged and attracts the negatively charged electrons.
The electron moves around the nucleus in the orbit due to the electromagnetic force.
The electromagnetic force:
The electromagnetic force is the fundamental force and the combination of electrical and magnetic force. This force acts between the charges.
Electrons around the nucleus in fixed orbits having fixed energy.
Electrons stay in the orbit due to electromagnetic force between the positively charged nucleus and electron.