Quantum Numbers
Which set of quantum numbers is NOT possible for an electron in an atom according to the rules governing quantum mechanical description of electrons?
Select the correct option:
Solution
n=4,l=3,ml=+4,ms=+1/2
The rules governing quantum numbers are: n must be a positive integer; l ranges from 0 to n-1; m_l ranges from -l to +l; m_s is either +1/2 or -1/2. Examining each option: n=3, l=2 is valid because l ≤ n-1=2; m_l=-2 is valid since |m_l| ≤ l=2; m_s=+1/2 is valid. n=2, l=1 is valid; m_l=0 is within range; m_s=-1/2 is valid. For n=4, l=3: l=3 ≤ n-1=3 is valid, but m_l=+4 is NOT valid because m_l can only range from -3 to +3, so +4 exceeds the limit. Hence this set is impossible. n=1, l=0, m_l=0, m_s=-1/2 perfectly satisfies all rules for a 1s electron. The invalid option n=4, l=3, m_l=+4 violates the rule that m_l cannot exceed l in magnitude. This is a standard NCERT/JEE concept on quantum number restrictions. Plausibility check: m_l=+4 with l=3 clearly breaks the boundary condition, confirming it as the impossible set.
🔒 Solution Hidden from View
Submit your answer to unlock the detailed step-by-step solution.
More quantum numbers Practice Questions
The maximum number of electrons that can have the quantum numbers n = 4 and mₛ = +½ is:
The maximum number of electrons that can have the quantum numbers n = 4 and mₛ = +½ is:
An electron in an atom has the quantum numbers n = 3, l = 2, mₗ = −1, mₛ = +½. The electron is prese...
An electron in an atom has the quantum numbers n = 3, l = 2, mₗ = −1, mₛ = +½. The electron is prese...
Approximate wavelength (nm) of the photon emitted when an electron in hydrogen atom drops from n=4 t...
Approximate wavelength (nm) of the photon emitted when an electron in hydrogen atom drops from n=4 t...
Which subshell is filled first according to the Aufbau principle?
Which subshell is filled first according to the Aufbau principle?
Which statement best explains Pauli's exclusion principle?
Which statement best explains Pauli's exclusion principle?
About This Question
- Subject
- chemistry
- Chapter
- atomic structure
- Topic
- quantum numbers
- Difficulty
- Easy
- Year
- 2025
Solution
Correct Answer:
n=4,l=3,ml=+4,ms=+1/2
The rules governing quantum numbers are: n must be a positive integer; l ranges from 0 to n-1; m_l ranges from -l to +l; m_s is either +1/2 or -1/2. Examining each option: n=3, l=2 is valid because l ≤ n-1=2; m_l=-2 is valid since |m_l| ≤ l=2; m_s=+1/2 is valid. n=2, l=1 is valid; m_l=0 is within range; m_s=-1/2 is valid. For n=4, l=3: l=3 ≤ n-1=3 is valid, but m_l=+4 is NOT valid because m_l can only range from -3 to +3, so +4 exceeds the limit. Hence this set is impossible. n=1, l=0, m_l=0, m_s=-1/2 perfectly satisfies all rules for a 1s electron. The invalid option n=4, l=3, m_l=+4 violates the rule that m_l cannot exceed l in magnitude. This is a standard NCERT/JEE concept on quantum number restrictions. Plausibility check: m_l=+4 with l=3 clearly breaks the boundary condition, confirming it as the impossible set.
This easy difficulty chemistry question is from the chapter atomic structure, covering the topic of quantum numbers. It appeared in the 2025 exam.
Looking for more practice? Explore all chemistry questions or browse atomic structure questions on RankGuru.