Isotopes and hydrogen: identify the incorrect statement among the following descriptions.

Introduction / Context:
Isotopes are nuclides of the same element with identical atomic number but different mass numbers. Hydrogen is a classic teaching example because its isotopes—protium, deuterium, and tritium—are widely discussed in chemistry and nuclear engineering.

Given Data / Assumptions:

• Neutral atoms considered (electrons equal protons).
• Natural abundance values are approximate.
• Periodic table placement is by atomic number Z.

Concept / Approach:
The key to spotting the incorrect statement is recalling that hydrogen has three well-known isotopes: 1H (protium), 2H or D (deuterium), and 3H or T (tritium). Therefore, the phrase “Hydrogen has two isotopes” is false. Deuterium abundance is roughly 0.015–0.016, giving an H:D ratio near 6400:1, which matches the figure given and is acceptable as an approximation.

Step-by-Step Solution:
Check isotope definition: same Z, different N.Hydrogen isotopes: protium, deuterium, tritium ⇒ not just two.Natural ratio H:D ≈ 6400:1 is reasonable.Conclusion: Option “Hydrogen has two isotopes” is incorrect.

Verification / Alternative check:
Standard references list three hydrogen isotopes; tritium is radioactive and less abundant in nature but well established, so counting only two is an error.

Why Other Options Are Wrong:
Option A: matches isotope definition.Option C: acceptable approximate ratio from natural abundance.Option E: isotopes share periodic position since Z is identical.Option D (“None of these”): cannot be correct because B is false.

Common Pitfalls:
Assuming tritium is excluded because it is radioactive; it is still an isotope.Confusing isotopes (same Z) with isobars (same A) or isotones (same N).

Final Answer:
Hydrogen has two isotopes.