Answer: Option (c) is the correct answer.
Atomic number means the number of protons present in an element. Whereas atomic mass means the sum of total number of protons and neutrons present in an element.
Also, it is known that when an atom is neutral then its number of protons equal number of electrons.
For example, atomic number of chromium is 24 this means that it contains 24 protons. Atomic mass of chromium is 52.
So, number of neutrons present in chromium is calculated as follows.
Atomic mass = no. of protons + no. of neutrons
52 = 24 + no. of neutrons
no. of neutrons = 52 – 24
Thus, we can conclude that there are 28 electrons in an uncharged atom of chromium.