Answer:
Molecular bonding cannot occur without electrons.
Step-by-step explanation:
In order to be 100% correct, the answers should be electrons, protons and neutrons. Since moleculas are formed by atoms and atoms are formed by electrons protons and neutrons.
However, if we consider only the bonding itself, the most important atomic particle is the electron. Molecular or convalent bonding happens when atoms share electrons pairs to reach stability.