Which of these particles contributes to the atomic mass of an atom?

Which of these particles contributes to the atomic mass of an atom?

• A. Proton
• B. Electron
• C. Neutron
• D. Both Proton and Neutron

Answer: (D)

The atomic mass of an atom is largely determined by the presence of protons and neutrons in the nucleus. Both of these particles have significant mass, with protons weighing approximately 1 atomic mass unit (amu) and neutrons also weighing about 1 amu. This mass contributes directly to the overall mass of the atom. Electrons, on the other hand, are much lighter than protons and neutrons, weighing only about 1/1836 of an amu, which is negligible in the calculations of atomic mass. Therefore, when determining the atomic mass, only protons and neutrons are counted. Since protons carry a positive charge and neutrons are neutral, they collectively make up the atomic mass with their combined total being the most significant contributor to the overall weight of the atom. Thus, stating that both protons and neutrons contribute to atomic mass accurately reflects their roles in the structure of an atom.

The atomic mass of an atom is largely determined by the presence of protons and neutrons in the nucleus. Both of these particles have significant mass, with protons weighing approximately 1 atomic mass unit (amu) and neutrons also weighing about 1 amu. This mass contributes directly to the overall mass of the atom.

Electrons, on the other hand, are much lighter than protons and neutrons, weighing only about 1/1836 of an amu, which is negligible in the calculations of atomic mass. Therefore, when determining the atomic mass, only protons and neutrons are counted.

Since protons carry a positive charge and neutrons are neutral, they collectively make up the atomic mass with their combined total being the most significant contributor to the overall weight of the atom. Thus, stating that both protons and neutrons contribute to atomic mass accurately reflects their roles in the structure of an atom.