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Nuclei — Physics STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 SciencePhysicsNuclei1 Mark
Question
For question, statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a) (b) (c) and (d) as given below.
  1. Both A and R are true, and R is the correct explanation of A.
  2. Both A and R are true, but R is NOT the correct explanation of A.
  3. A is true, but R is false.
  4. A is false and R is also false.
Assertion (A): $_7^{14}\text{N}$ is stable.
Reason (R): Nuclei having an odd number of protons and an odd number of neutrons are generally less stable than the one having even number of protons and even number of neutrons.
✓

Answer

  1. Both A and R are true, but R is NOT the correct explanation of A.
Explanation:
Nitrogen is a stable element. Those elements which have an odd number of protons and an odd number of neutrons are generally unstable. $_7^{14}\text{N}$ has 7 protons and 7 neutrons i.e., odd number of both protons and neutrons, but it is an exception. It is a stable element.

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