Which of the following is NOT an isotope of hydrogen?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is Option 1 i.e. Lithium
Hydrogen has three naturally occurring isotopes: Protium (¹H), Deuterium (²H or D), and Tritium (³H or T). These isotopes differ in the number of neutrons they contain. Lithium, on the other hand, is a completely different element with atomic number 3, and is not an isotope of hydrogen.