Which of the following represents a pair of isotopes?
A) 14C, 14N
B) 1H, 2H
C) 32S, 32S-2
D) O2, O3
The correct answer and explanation is :
The correct answer is B) 1H, 2H.
Explanation:
Isotopes are atoms of the same element that have the same number of protons (atomic number) but different numbers of neutrons. This results in different atomic masses but identical chemical properties. Let’s analyze the choices:
A) 14C, 14N:
- Carbon (C) and Nitrogen (N) are different elements, with different atomic numbers (6 for Carbon and 7 for Nitrogen), so they cannot be isotopes of each other. Isotopes must be the same element.
B) 1H, 2H:
- These are isotopes of Hydrogen. Both have the same number of protons (1 proton), which makes them both hydrogen atoms, but they have different numbers of neutrons. The isotope 1H (protium) has no neutrons, while 2H (deuterium) has one neutron. Therefore, they are isotopes of the same element.
C) 32S, 32S-2:
- 32S represents the sulfur isotope with an atomic mass of 32 (16 protons and 16 neutrons). 32S-2 refers to the ion of 32S with two extra electrons, making it a negatively charged ion, not a different isotope. The charge doesn’t affect the isotope status because isotopes differ in neutrons, not in electrons.
D) O2, O3:
- O2 and O3 are molecules, not isotopes. O2 is dioxygen, a molecule with two oxygen atoms, and O3 is ozone, a molecule with three oxygen atoms. These are molecular forms of oxygen, not different isotopes.
Conclusion:
B) 1H, 2H is the correct answer because both represent isotopes of hydrogen, differing in the number of neutrons.
