Rubbing a polythene strip on wool causes some of the outer electrons in the wool to move over to the polythene strip. As the polythene gains electrons it becomes negatively charged. The wool looses electrons and is left with a net positive charge (more protons to electrons).
Static electricity is caused by the transfer of charge.
Atoms are made up of protons, neutrons and electrons each with their own properties.
Protons have a Positive (+) charge.
Electrons have a Negative (-) charge.
Neutrons are Neutral (no charge).
The positive charges (protons) are held in the nucleus of the atom.