Question

An atom contains 12 protons, 12 electrons, and 13 neutrons.
Which of the following combinations of particles is an isotope of that atom?

• A. Protons-12, Electrons-12, Neutrons-12
• B. Protons-12, Electrons-13, Neutrons-13
• C. Protons-13, Electrons-12, Neutrons-12
• D. Protons-13, Electrons-13, Neutrons-12
• E. Protons-14, Electrons-12, Neutrons-12

Answer 1

The correct option is A Protons-12, Electrons-12, Neutrons-12

Isotopes are the elements having the same atomic number i.e same number of protons which in turn is equal to same number of electrons. Number of protons and electrons are equal as the atom is electrically neutral. So, the only option is A.