Atheory is set of statements or principles devised to explain a group of facts or phenomena, especially one that has been repeatedly tested and is widely accepted. true or false

The answer your looking for is true hope it helps:)

The proton has a positive charge while the neutron has no charge they both make up the nucleus of the atom while the elections have a negative charge and surround the nucleus of the atom. the protons and electrons are used to calculate the atom's mass whereas the neutrons don't affect the mass