The question asks about the definition of the mass number of an atom. To answer this, we need to recall the basic structure of an atom and the properties of its subatomic particles.
Therefore, the mass number is the sum of protons and neutrons.
C) Protons and neutrons — The mass number of an atom is defined as the total number of protons and neutrons in its nucleus. These two particles contribute almost all of the atom's mass.
The question asks for the defining characteristic of isotopes. To answer this, we need to recall the definitions of atomic number, mass number, and how they relate to protons, neutrons, and electrons in an atom.
C) Same atomic number, different mass numbers — This statement perfectly aligns with the definition of isotopes. For example, Carbon-12 (\(^{12}_{6}\text{C}\)) has 6 protons and 6 neutrons, while Carbon-14 (\(^{14}_{6}\text{C}\)) has 6 protons and 8 neutrons. Both are carbon (same atomic number, 6), but they have different mass numbers (12 and 14).
The question asks for the definition of isobars. To answer this, we need to recall the definitions of key terms in atomic structure: atomic number, mass number, isotopes, isobars, and isotones.
A) Same mass number but different atomic numbers. This is the precise definition of isobars. For example, Carbon-14 (\(^{14}_6\text{C}\)) and Nitrogen-14 (\(^{14}_7\text{N}\)) are isobars. Both have a mass number of 14, but their atomic numbers are 6 and 7, respectively.
The question asks for the definition of isotones. We need to recall the definitions of different types of nuclei based on their atomic number, mass number, and neutron number.
C) Isotones are nuclei having the same number of neutrons. This aligns with the definition derived in the step-by-step explanation.
The question asks about the fundamental postulate upon which Bohr's atomic model is built. We need to recall the key assumptions made by Niels Bohr to explain the stability of atoms and the discrete nature of atomic spectra.
Correct Option: D) Quantization of angular momentum — This is a fundamental postulate of Bohr's atomic model, stating that an electron can only revolve in orbits where its angular momentum is an integral multiple of \(h/(2\pi)\).
The question asks for the maximum number of electrons that can be accommodated in the L-shell of an atom. This can be determined using the formula for the maximum number of electrons in a given electron shell.
D) 8 is the correct answer because the L-shell corresponds to the principal quantum number \(n=2\), and using the formula \(2n^2\), the maximum number of electrons is \(2 \times 2^2 = 8\).