This involves negatively charged particles (electrons) jumping to positively charged objects. When you rub the balloons against the fabric they become negatively charged. They take some of the electrons from the fabric and leave them positively charged.
Explanation:
Negative charges attract to positive charges. If a balloon is not rubbed with the wool cloth, it has an equal amount of negative to positive charges, so it will attract to a rubbed balloon. When both balloons are rubbed with the wool cloth, the both receive negative charges, so they will repel each other.
The atomic mass is determined by the number of protons and neutrons in a atoms for example oxygen has eight protons and neutrons which gives oxygen and atomic mass of 16
