Bohr's model of the atom included a positively charged nucleus orbited by negatively charged electrons.
The atom is made up of 3 particles:
Proton - positively charged particle
Neutron - neutral or no charge
Electron - negatively charged
The protons and neutrons make up the nucleus of the atom and because the neutrons have no charge, the nucleus is positively charged because of the presence of the protons. The electrons orbit it because they are attracted by the charge of the nucleus because they are oppositely charged.