NEETChemistryStructure of Atom
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): An electron cannot have the quantum numbers n=3, l=2, m_l=-3, m_s=+1/2 . Reason (R): For a given principal quantum number n , the azimuthal quantum number l can have values from 0 to n , and the magnetic quantum number m_l can have values from -l to +l . In the light of the above statements, choose
Options
- ABoth (A) and (R) are correct and (R) is the correct explanation of (A)
- B(A) is correct but (R) is not correct
- C(A) is not correct but (R) is correct
- DBoth (A) and (R) are correct but (R) is not the correct explanation of (A)
Correct answer
B. (A) is correct but (R) is not correct
Step-by-step solution
For a given principal quantum number n , the allowed values of the azimuthal quantum number l are from 0 to n-1 . Thus, for n=3 , l can be 0, 1 , or 2 . The Reason statement incorrectly claims l can go up to n , so (R) is not correct. For a given value of l , the magnetic quantum number m_l can have integer values from -l to +l . For l=2 , the possible values of m_l are -2, -1, 0, +1, +2 . An electron cannot have m_l=-3 when l=2 . Therefore, the Assertion (A) is correct. Hence, (A) is correct but (R) is not correct