Question

Do the proton and the neutron have exactly the same mass? How do the masses of the proton and the neutron compare to the mass of the electron? Which particles make the greatest contribution to the mass of an atom? Which particles make the greatest contribution to the chemical properties of an atom?

Short answer

The proton and the neutron do not have exactly the same mass; the proton has a mass of approximately 1.6726219 × 10^{-27} kg, while the neutron has a mass of approximately 1.6749274 × 10^{-27} kg. Both proton and neutron masses are much greater than the electron's mass of approximately 9.10938356 × 10^{-31} kg. The mass of an atom is primarily determined by the combined mass of its protons and neutrons, while its chemical properties are determined by the number and arrangement of its electrons in energy levels surrounding the nucleus.

Step-by-step solution

Determine the mass of a proton and a neutron

The mass of a proton is approximately 1.6726219 × 10^{-27} kg, while the mass of a neutron is approximately 1.6749274 × 10^{-27} kg. These values are very close, but they are not identical, meaning that the proton and the neutron do not have exactly the same mass.

Compare the masses of proton, neutron, and electron

The mass of an electron is approximately 9.10938356 × 10^{-31} kg, which is significantly smaller than both the proton and the neutron's mass. The mass of a proton is approximately 1,836 times greater than the mass of an electron, and the mass of a neutron is approximately 1,839 times greater than the mass of an electron.

Identify particles contributing to the mass of an atom

The mass of an atom is primarily determined by the combined mass of its protons and neutrons, which are collectively called nucleons. Electrons contribute very little to the mass of an atom because their mass is so much smaller compared to protons and neutrons. Hence, protons and neutrons make the greatest contribution to the mass of an atom.

Identify particles contributing to the chemical properties of an atom

The chemical properties of an atom are determined by the number of electrons it has, as well as their arrangement in "orbitals," or energy levels surrounding the nucleus. The positively charged protons in the nucleus influence the behavior of the negatively charged electrons. However, it is the electrons that participate in chemical reactions and form bonds with other atoms, giving rise to the chemical properties of an element. Thus, electrons make the greatest contribution to the chemical properties of an atom.