a. The two particles that make up the nucleus of the atom are protons and neutrons. Protons are positively charged particles, while neutrons have no charge (they are neutral).
b. The atomic mass of an atom is defined as the weighted average mass of an atom's isotopes, measured in atomic mass units (amu). It accounts for both the number of protons and neutrons in the nucleus, as these particles contribute the majority of the atom's mass. The atomic mass also reflects the relative abundance of each isotope of an element.
c. Electrons contribute only a very small amount to the overall mass of the atom. This is because electrons are much lighter than protons and neutrons. While the mass of an electron is approximately \(1/1836\) of that of a proton, it is still present and contributes to the atom's properties, especially in chemical reactions and bonding. However, for most practical purposes, the mass of the atom is dominated by the protons and neutrons in the nucleus, and the contribution of the electrons to the overall mass is negligible.
1 answer