Question

Which of the following statements is false regarding hydrogen ?

• A. It has two isotopes.
• B. In periodic table hydrogen is placed separately above group 1.
• C. When one electron is lost it forms proton.
• D. It does not exist freely.

Hint:

Hydrogen has three isotopes, protium, deuterium and tritium, so the statement about two isotopes is the false one.

Answer 1

The Correct Option is A

Step 1: Understand the question
We need the statement that is false. Check each against the known facts about hydrogen.

Step 2: Check statement (A)
Hydrogen has three isotopes: protium (\(^1\text{H}\)), deuterium (\(^2\text{H}\)) and tritium (\(^3\text{H}\)). Saying it has only two is wrong, so (A) is FALSE.

Step 3: Check statement (B)
Hydrogen has one valence electron like alkali metals but also needs one electron to complete its shell like halogens. So it is placed separately at the top, above group 1. (B) is TRUE.

Step 4: Check statements (C) and (D)
Losing its single electron leaves a bare proton, \(\text{H} \to \text{H}^+ + e^-\), so (C) is TRUE. Hydrogen is very reactive and light, so it is found in compounds like water and hydrocarbons, not freely in nature. (D) is TRUE.

Final Answer:
Only the statement about two isotopes is false. This is option (A). \[ \boxed{\text{(A) }\text{It has two isotopes}} \]