The positively charged particle found in nucleus are protons . They need to be kept separated as if the protons of two different particles are brought together , due to same charge they will repel each other.
If electrons are considered , they carry negative charge on them and they are present outside nucleus . Neutron have no charge on it although they are present in nucleus .
Quarks are present in both neutrons and protons . They carry both positive and negative charges .
Hence we can say protons are the positively charges particles which need to be separated .
