Get detailed and accurate responses to your questions on IDNLearn.com. Discover comprehensive answers to your questions from our community of experienced professionals.
Explanation:
The Correct Answer is Option 3 i.e 20. The number of neutrons within the nucleus of a given atom can be found by subtracting the atomic number from the atomic mass i.e difference between the mass number of the atom and the atomic number. Number of neutrons = 39 - 19 = 20.