In an atom, there are 12 protons and 12 neutrons in the nucleus. Now, imagine that all the electrons are replaced with some hypothetical particles that have the same charge as electrons but are 500 times heavier. What effect will this replacement have on the atom's:

(A) Atomic number

(B) Atomic mass

(C) Mass number

(D) Overall charge

The atom contains 12 protons and 12 neutrons. Replacing electrons with heavier particles having the same negative charge will not affect the nucleus.

(A) The atomic number is equal to the number of protons in the nucleus. Since the protons remain unchanged (12), the atomic number remains the same, i.e., 12.

(B) The atomic mass will increase because the hypothetical particles are 500 times heavier than electrons. Atomic mass is approximately the total mass of all particles in the atom. However, if you make all 12 electrons 500 times heavier, each new particle now weighs roughly 27% of a proton's mass. Together, these 12 heavy particles cause a noticeable increase in total atomic mass.

(C) The mass number will remain 24 because it depends only on the number of protons and neutrons present in the nucleus.

(D) The hypothetical particles carry the same charge as electrons, i.e., -1 each. Since the number of negatively charged particles (12) is equal to the number of protons (12), the total positive and negative charges balance each other. Therefore, the overall charge of the atom remains zero.