Proton vs. Neutron — What's the Difference?

Protons are essential components of an atom's nucleus, carrying a positive electric charge. Their number determines the chemical element's identity, as each element on the periodic table corresponds to a unique proton count. For example, hydrogen has one proton, making it the simplest element. On the other hand, neutrons are electrically neutral particles also found in the nucleus. They don't affect the chemical properties of an element but add to the atom's mass. Neutrons play a critical role in stabilizing the nucleus, especially in heavier elements where repulsive forces between protons are stronger.

The mass of protons and neutrons is nearly the same, yet not identical. Protons have a slightly lower mass than neutrons, a difference that is crucial for nuclear reactions, including fusion and fission. While the mass of a proton is about 1.6726 x 10^-27 kilograms, that of a neutron is slightly higher, approximately 1.6749 x 10^-27 kilograms. This slight difference affects the stability and energy of atoms.

Protons determine the atomic number of an element, which is fundamental to its position on the periodic table and its chemical behavior. This atomic number is equal to the number of protons in an atom's nucleus. In contrast, the number of neutrons in an atom contributes to the isotope of that element. Isotopes of an element have the same number of protons but different numbers of neutrons, leading to variations in atomic mass and sometimes in stability.

In terms of interaction, protons within the nucleus are affected by the electromagnetic force due to their positive charge, which repels them from each other. The strong nuclear force, however, overcomes this repulsion at very short distances, binding protons and neutrons together in the nucleus. Neutrons, lacking electric charge, do not experience electromagnetic repulsion, which helps them to act as a nuclear 'glue,' providing stability to the nucleus by mitigating the repulsive forces between protons.

Protons and neutrons are both subject to radioactive decay under certain conditions, transforming from one into another through processes such as beta decay. This transformation alters the balance of protons and neutrons in the nucleus, leading to the transmutation of elements. During beta decay, a neutron can decay into a proton, an electron, and an antineutrino, changing the atomic number and, consequently, the element itself. Conversely, protons are stable in most conditions within atoms but can be transformed in high-energy environments or reactions.