Which subatomic particles significantly contribute to an atom's mass? I think a proton does, but I'm not totally sure.
A proton does. A neutron does. An electron does not affect the mass of an atom significantly.
You are correct! Protons are one of the subatomic particles that significantly contribute to an atom's mass. To explain how you can arrive at this answer, let me break it down for you:
1. Start by understanding what makes up an atom. Atoms consist of three main subatomic particles: protons, neutrons, and electrons. Protons and neutrons are found in the atom's nucleus, while electrons orbit around the nucleus.
2. Next, let's consider the masses of these particles. A proton has a mass of approximately 1 atomic mass unit (amu) or 1.67 x 10^-27 kg, while a neutron has a mass that is slightly larger, also around 1 amu. In comparison, electrons have a much smaller mass of approximately 1/1836 amu.
3. Since protons and neutrons have a significant mass and are located in the nucleus, they contribute most of the atom's mass. The protons and neutrons together form the atom's atomic mass or atomic weight.
4. Electrons, despite their small mass, do play a role in determining the overall properties of an atom, such as its chemical behavior and reactivity. However, due to their extremely low mass, they contribute very little to an atom's total mass.
In summary, it is correct to say that protons significantly contribute to an atom's mass, along with neutrons. Electrons, although important for the atom's behavior, have negligible mass compared to protons and neutrons.