Objects can be positively charged, negatively charged or neutral (no charge).
A substance that gains electrons becomes negatively charged, while a substance that loses electrons becomes positively charged.
If the charges are the same - they repel
If the charges are opposite - they attract
If one is charged and the other is not - they attract
Why does a balloon stick to the wall?
A balloon is more negatively charged when rubbed against hair or a similar surface. A wall doesn't have a particular charge, which means it doesn't conduct…