Final answer:
The subatomic particle responsible for chemical reactions is the electron. Protons and neutrons, which are found in the nucleus, do not directly participate in chemical reactivity.
Step-by-step explanation:
The subatomic particle responsible for participating in chemical reactions, including the breaking and forming of bonds, is the electron. Electrons inhabit the outer regions of atoms and engage in interactions that lead to the creation or disruption of chemical bonds. This subatomic particle has a negative charge, represented by the symbol e-, and is significantly lighter than the other subatomic particles such as protons and neutrons, which make up the atomic nucleus.
While protons and neutrons, collectively known as nucleons, are found in the nucleus of an atom and contribute to its mass, they do not play a direct role in the chemical properties of elements. This is because chemical reactions involve the outer electrons of atoms rather than the nucleus itself. Protons have a positive charge, represented by p+, and neutrons are neutral, typically represented as n or n0.