The nucleus of an atom contains Electrons and Protons 

 

Solution:

Concept: Atom as a whole is neutral, it contains proton's positive charge as well as negative charges. A neutral atom has a charge balance, atoms have an equal number of  electrons and protons when it has an undisturbed number of electrons and protons (equal negative electric charge and positive electric charge)

Hence, The nucleus of an atom contains protons and neutrons