Step-by-step explanation:
Nucleus of an atom consists of two sub-atomic particles.These are protons and neutrons. On the other hand, electrons are the third sub-atomic particles which revolve around the nucleus of an atom.
Protons have a positive charge whereas neutrons have no charge and electrons have a negative charge.
Due to positive charge of protons, nucleus of an atom acquires a positive charge.
Therefore, we can conclude that protons are the particles give the nucleus its positive charge.