Answer: Option (A) and (D) are correct.
Explanation:
Atomic number means the number of protons holded by an atom. On the other hand, atomic mass means the sum of total number of protons and neutrons holded by an atom.
For example, in an isotope of oxygen as oxygen-15 with an atomic number 8 means that there are 8 protons.
So, number of neutrons present in oxygen-15 will be as follows.
Atomic mass = no. of protons + no. of neutrons
15 = 8 + no. of neutrons
no. of neutrons = 15 - 8 = 7
Hence, this isotope of oxygen atom has 8 protons and 7 neutrons.
