Question

Which of the following pair is/are correctly matched?

Isotopes : Atoms with same atomic number but different atomic mass
Isobars : Atoms with same number of neutrons but different atomic number
Isotones : Atoms with same mass number but different atomic number
Select the correct answer using the code given below:

• A. 1, 2 and 3
• B. 1 only
• C. 1 and 2 only
• D. 2 only

Hint:

Remember:

textbfIsotopes → Same (Z), different (A)
textbfIsobars → Same (A), different (Z)
textbfIsotones → Same neutrons, different (Z)

Answer 1

The Correct Option is B

Step 1: Check statement 1 (Isotopes). Isotopes are atoms with:

Same atomic number
Different mass number
Hence, statement (1) is correct. Step 2: Check statement 2 (Isobars). Isobars are atoms with:

Same mass number
Different atomic number
But the statement says “same number of neutrons”, which is incorrect. Hence, statement (2) is incorrect. Step 3: Check statement 3 (Isotones). Isotones are atoms with:

Same number of neutrons
Different atomic number
But the statement says “same mass number”, which is incorrect. Hence, statement (3) is incorrect. Step 4: Final conclusion. Only statement (1) is correctly matched. \[ \boxed{\text{(B) 1 only}} \]