Question

15. The volume of a nucleus in an atom is proportional to the :
(A) mass number
(B) proton number
(C) neutron number
(D) electron number​

Answer 1

Answer:

Most nuclei are approximately spherical. The average radius of a nucleus with A nucleons is R = R0A1/3, where R0 = 1.2*10-15 m. The volume of the nucleus is directly proportional to the total number of nucleons. This suggests that all nuclei have nearly the same density.

Answer 2

A) Mass Number is proportional to the volume of the nucleus in an atom

Mass Number

• Mass Number refers to the sum of protons and neutrons (combined called nucleons) present in the nucleus of the atom.
• It is denoted by A.
• It is also called Atomic Mass.

Volume of Nucleus

• To find the volume of the nucleus, we always consider the nucleus to be a spherical object such that its radius is R = R₀$A^{1/3}$ where R₀ has a constant value of 1.25 × 10⁻¹⁵ m.
• Therefore, the volume of the spherical nucleus is $V = \frac{4}{3} \pi R^3 = \frac{4}{3} \pi ({R_0 A^{1/3}})^3 = \frac{4}{3} \pi R_0^3 A$
• The above formula for volume implies that the volume of the nucleus is proportional to the mass number.

The mass number is the number of nucleons of the atom. The volume of the nucleus is $V = \frac{4}{3} \pi R_0^3 A$ which implies that the volume is directly proportional to the mass number (A).