Question

Which element has three isotopes that are each known by a different name?

• A. Helium
• B. Oxygen
• C. Carbon
• D. Hydrogen

Hint:

Think of the special names protium, deuterium and tritium. Which element do they belong to?

Answer 1

The Correct Option is D

Step 1: Isotopes are atoms of the same element with the same number of protons but a different number of neutrons.

Step 2: Most elements name their isotopes with the element name plus a mass number, such as carbon-12, carbon-13 and carbon-14. Hydrogen is the one common exception.

Step 3: Hydrogen has three well known isotopes, each with its own separate name: protium, the ordinary form with one proton and no neutron, deuterium, with one proton and one neutron, and tritium, with one proton and two neutrons, which is radioactive.

Since these three isotopes of hydrogen have distinct individual names, the correct answer is option D.