The proton has a charge equal in magnitude but opposite in sign to that of:

An atom is composed of protons that have a positive charge, a neutron with no charge, and an electron with a negative charge. Protons and neutrons are found in the nucleus of the atom while electrons orbit a positive nucleus. Protons have a positive electrical charge of one (+1) that is equal in magnitude but opposite in sign to that of an electron that has a charge of negative one (-1).