JEE Main · Chemistry · Structure of Atom
Quantum Numbers: JEE Main previous year questions
52 questions in the 108 JEE Main shifts Lumi analysed, in 8 of 8 years. Pattern: Asked most years. 20 came in 2024–26. Here is how it is asked and which ideas come back.
- Questions
- 52
- in 50 of 108 shifts
- Years asked
- 8/8
- last asked 2026
- Weighted estimate
- 0.5
- model; history: 0.5 a shift on average, typically 0.3–0.6
Key findings
- 01
Asked in 8 of 8 years with analysed shifts and in 50 of 108 shifts: 52 questions, #50 of 196 topics. It came in every year with analysed shifts.
- 02
53% of its questions since 2020 tested an idea no earlier year had asked; 13 repeated an idea from the year before.
- 03
The most repeated idea is Aufbau Principle and n+l Rule, asked 8 times in 8 shifts (2020, 2021, 2022, 2024, 2026), most often as “order/ranking of orbital energies”.
- 04
JEE Main has asked 23 of the 54 ideas in this topic; 20 have never been asked, directly or inside another question.
- 05
Mostly asked as single correct (42%); 29% need a numerical answer, 60% are easy and 2% hard.
- 06
The skill tested most is application (38%), then conceptual (21%).
Questions a shift, year by year
Out of the 25 Chemistry questions in a shift. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift.
Raw count: 2017: 1 in 1 shift · 2020: 3 in 12 shifts · 2021: 10 in 24 shifts · 2022: 14 in 24 shifts · 2023: 4 in 12 shifts · 2024: 10 in 18 shifts · 2025: 5 in 8 shifts · 2026: 5 in 9 shifts.
- Up to 2023
- 0.4
- a shift, of 25
- Since 2024
- 0.6
- 0.1
- Usual gap
- 1.3 yrs
- between years asking it
- Shifts with it
- 50/108
- 46% of analysed shifts
Recent framings
- match list on orbital nodes
- count correct statements on atomic structure
- count correct statements on orbitals
Revise first
- Aufbau Principle and n+l Rule · asked 2020, 2021, 2022, 2024, 2026
- Anomalous Electron Configurations · asked 2022, 2024, 2025, 2026
- Calculation of Radial and Angular Nodes · asked 2021, 2022, 2023, 2024, 2026
How it is asked
Difficulty, format and skill
Across all 52 questions on Quantum Numbers since 2017.
Difficulty
QUESTIONS- Easy31 · 60%
- Medium20 · 38%
- Hard1 · 2%
Format
SHARE- Single correct · 22 Q42%
- Numerical value · 15 Q29%
- Other · 10 Q19%
- Match the list · 2 Q4%
- Diagram based · 2 Q4%
- Two statements · 1 Q2%
Skill tested
SHARE- Application · 20 Q38%
- Conceptual · 11 Q21%
- Calculation · 11 Q21%
- Recall · 5 Q10%
- Multi-step · 3 Q6%
- Data or graph · 2 Q4%
Repeats
New idea, or one asked before?
Each column is a year. Blue questions tested an idea no earlier year had asked; navy ones went back to an idea from an earlier year. 2017 is the first year, so everything in it counts as new. Heights are question counts, and Lumi analysed 1 to 24 shifts a year, so compare the split inside a column rather than heights across years.
- Idea asked for the first time
- Idea asked in an earlier year
Coverage of the topic
JEE Main has asked 23 of the 54 ideas in this topic. 20 have never been asked yet.
- Asked directly23 · 43%
- Touched inside another question11 · 20%
- Never asked20 · 37%
Ideas come from Lumi’s JEE syllabus map. A never-asked idea is not a safe skip: across all of JEE Main, 22% of questions since 2024 tested an idea no earlier year had asked.
Drill down
Chapter, idea, question
Every idea JEE Main tested in this topic, with its eight years. Open one to read the questions.
20 ideas inside
Squares are the 8 years with analysed shifts, 2017 to 2026. A number is the questions that year when there is more than one; the shade is scaled to one shift, so a year with more analysed shifts (1 to 24 a year) does not look darker. Share is of the level above.
Ideas
Every idea inside this topic
23 different ideas were tested; 9 came more than once.
order/ranking of orbital energies
Single correct · 8 shifts · 1 numericalmatch list on orbital nodes
Single correct · 8 shifts · 2 numericalcount orbitals from quantum numbers
Numerical value · 7 shifts · 5 numericalcount correct statements on atomic structure
Other · 4 shiftsidentify disallowed set of quantum numbers
Numerical value · 3 shifts · 1 numericalorbital angular momentum of s and p electrons
Numerical value · 2 shifts · 1 numericalorder/ranking of unpaired electrons
Numerical value · 2 shifts · 1 numericalquantum numbers of valence electron
Single correct · 2 shiftsidentify group of isoelectronic species
Single correct · 2 shiftscount correct reasons for half-filled stability
Other · 1 shifttrue statement selection on orbitals
Other · 1 shiftcount correct statements on electronic configuration
Other · 1 shiftstatement i/ii on degenerate orbitals
Two statements · 1 shiftcount electrons with given quantum numbers
Numerical value · 1 shift · 1 numericalcount correct statements on atomic structure
Numerical value · 1 shift · 1 numericalunpaired electrons from magnetic moment
Numerical value · 1 shift · 1 numericalidentify degenerate orbitals from quantum numbers
Other · 1 shiftidentify probability density plot for orbital
Diagram based · 1 shiftspecies isoelectronic with al3+
Single correct · 1 shiftvalence shell configuration of element in group
Single correct · 1 shiftcount f electrons in ground state of actinide
Numerical value · 1 shift · 1 numericalidentify radial distribution plot of orbital
Diagram based · 1 shiftelectronic configuration under hypothetical quantum rules
Single correct · 1 shift
| Idea | Years asked | Times | Shifts | Format | Numerical |
|---|---|---|---|---|---|
| Aufbau Principle and n+l Ruleorder/ranking of orbital energies | 8 | 8 | Single correctApplication | 1 | |
| Calculation of Radial and Angular Nodesmatch list on orbital nodes | 8 | 8 | Single correctCalculation | 2 | |
| Magnetic Quantum Numbercount orbitals from quantum numbers | 7 | 7 | Numerical valueApplication | 5 | |
| Anomalous Electron Configurationscount correct statements on atomic structure | 4 | 4 | OtherApplication | – | |
| Validity of Quantum Number Setsidentify disallowed set of quantum numbers | 3 | 3 | Numerical valueApplication | 1 | |
| Orbital and Spin Angular Momentumorbital angular momentum of s and p electrons | 2 | 2 | Numerical valueCalculation | 1 | |
| Counting Unpaired Electronsorder/ranking of unpaired electrons | 2 | 2 | Numerical valueApplication | 1 | |
| Quantum Numbers of the Differentiating Electronquantum numbers of valence electron | 2 | 2 | Single correctApplication | – | |
| Configurations of Isoelectronic Speciesidentify group of isoelectronic species | 2 | 2 | Single correctApplication | – | |
| Calculation of Exchange Energy Pairscount correct reasons for half-filled stability | 1 | 1 | OtherConceptual | – | |
| Orbital Boundary Surface Diagramstrue statement selection on orbitals | 1 | 1 | OtherConceptual | – | |
| Spin Quantum Numbercount correct statements on electronic configuration | 1 | 1 | OtherMulti-step | – | |
| Degeneracy in Hydrogen-like Speciesstatement i/ii on degenerate orbitals | 1 | 1 | Two statementsConceptual | – | |
| Maximum Electrons in a Subshellcount electrons with given quantum numbers | 1 | 1 | Numerical valueMulti-step | 1 | |
| Interpreting Radial Probability Curvescount correct statements on atomic structure | 1 | 1 | Numerical valueConceptual | 1 | |
| Spin-Only Magnetic Momentunpaired electrons from magnetic moment | 1 | 1 | Numerical valueCalculation | 1 | |
| Hydrogen vs Multi-Electron Degeneracyidentify degenerate orbitals from quantum numbers | 1 | 1 | OtherApplication | – | |
| Interpreting Radial Wavefunction Graphsidentify probability density plot for orbital | 1 | 1 | Diagram basedData or graph | – | |
| Isoelectronic Species Configurationsspecies isoelectronic with al3+ | 1 | 1 | Single correctConceptual | – | |
| Predicting Periodic Table Positionvalence shell configuration of element in group | 1 | 1 | Single correctApplication | – | |
| Anomalous Configurations of Heavy Metalscount f electrons in ground state of actinide | 1 | 1 | Numerical valueRecall | 1 | |
| Interpreting Radial Probability Distribution Graphsidentify radial distribution plot of orbital | 1 | 1 | Diagram basedData or graph | – | |
| Azimuthal Quantum Numberelectronic configuration under hypothetical quantum rules | 1 | 1 | Single correctApplication | – |
Times and shifts count every analysed shift. Across JEE Main, 78% of questions since 2024 went back to an idea an earlier year had asked; the rest were new. All repeated ideas
Every question
Quantum Numbers questions, year by year
The newest 40 show their opening words as they appeared in the official paper; older ones name the idea they tested. Open one for its options and the official answer.
JEE Main 20265 questions in 4 shifts
- 4 Apr, Shift 1Q53Which of the following is correct set of quantum numbers of electron in Chromium (Atomic number ) in accordance…
Idea: Aufbau Principle and n+l Rule
MediumSingle correct - 5 Apr, Shift 1Q52Arrange the following atomic orbitals of multi electron atoms in order of increasing energy. A. B.…
Idea: Aufbau Principle and n+l Rule
MediumOther - 5 Apr, Shift 1Q53Identify the correct statements from the following : A. Heisenberg uncertainty principle is applicable to electrons. B. The size of …
Idea: Anomalous Electron Configurations
Asked the year beforeEasyOther - 5 Apr, Shift 2Q52Which of the following statement(s) is/are true ? A. If two orbitals have the same value of , the orbital with lower value of n…
Idea: Aufbau Principle and n+l Rule
MediumOther - 6 Apr, Shift 1Q53Match the LIST-I with LIST-II List-I (Orbital) | List-II (Radial nodes and nodal plane) A. 2s | I. 1 Radial node + two nodal planes B. 3s…
Idea: Calculation of Radial and Angular Nodes
MediumMatch the list
JEE Main 20255 questions in 5 shifts
- 2 Apr, Shift 2Q52Which of the following statements are true ? (A) The subsidiary quantum number describes the shape of the orbital occupied by the…
Idea: Orbital Boundary Surface Diagrams
New ideaMediumOther · figure - 3 Apr, Shift 2Q52For electrons in '2s' and '2p' orbitals, the orbital angular momentum values, respectively are :
Idea: Orbital and Spin Angular Momentum
EasySingle correct - 4 Apr, Shift 2Q51Consider the ground state of chromium atom . How many electrons are with Azimuthal quantum number and respectively ?
Idea: Anomalous Electron Configurations
Asked the year beforeEasySingle correct - 7 Apr, Shift 2Q51The extra stability of half-filled subshell is due to : (A) Symmetrical distribution of electrons (B) Smaller coulombic repulsion energy…
Idea: Calculation of Exchange Energy Pairs
New ideaMediumOther - 8 Apr, Shift 2Q51Correct statements for an element with atomic number 9 are A. There can be 5 electrons for which and 4 electrons for…
Idea: Spin Quantum Number
New ideaMediumOther
JEE Main 202410 questions in 9 shifts
- 4 Apr, Shift 2Q81The maximum number of orbitals which can be identified with n = 4 and = 0 is ________.
Idea: Magnetic Quantum Number
EasyNumerical value - 5 Apr, Shift 2Q81In an atom, total number of electrons having quantum numbers , and is ________.
Idea: Magnetic Quantum Number
MediumNumerical value - 6 Apr, Shift 2Q69Arrange the following elements in the increasing order of number of unpaired electrons in it. (A) Sc (B) Cr (C) V (D) Ti (E) Mn Choose the…
Idea: Counting Unpaired Electrons
EasyOther - 9 Apr, Shift 1Q61Compare the energies of following sets of quantum numbers for multielectron system. (A) (B) (C) (D)…
Idea: Aufbau Principle and n+l Rule
EasySingle correct - 1 Feb, Shift 2Q61The number of radial node/s for 3p orbital is :
Idea: Calculation of Radial and Angular Nodes
Asked the year beforeEasySingle correct - 27 Jan, Shift 1Q82The number of electrons present in all the completely filled subshells having and is __________. (Where =…
Idea: Maximum Electrons in a Subshell
New ideaMediumNumerical value - 29 Jan, Shift 1Q61The correct set of four quantum numbers for the valence electron of rubidium atom (Z = 37) is :
Idea: Quantum Numbers of the Differentiating Electron
New ideaEasySingle correct - 30 Jan, Shift 1Q61Given below are two statements : Statement (I) : The orbitals having same energy are called as degenerate orbitals. Statement (II) : In…
Idea: Degeneracy in Hydrogen-like Species
New ideaEasyTwo statements - 30 Jan, Shift 1Q66Match List - I with List - II. List - I (Species) List - II (Electronic distribution) (A) (I) (B)…
Idea: Anomalous Electron Configurations
MediumMatch the list - 31 Jan, Shift 2Q62The four quantum numbers for the electron in the outer most orbital of potassium (atomic no. 19) are
Idea: Quantum Numbers of the Differentiating Electron
New ideaEasySingle correct
JEE Main 20234 questions in 4 shifts
- 8 Apr, Shift 2Q81The number of atomic orbitals from the following having 5 radial nodes is ____________. 7s, 7p, 6s, 8p, 8d
Idea: Calculation of Radial and Angular Nodes
Asked the year beforeEasyNumerical value - 10 Apr, Shift 2Q89For a metal ion, the calculated magnetic moment is 4.90 BM. This metal ion has ____________ number of unpaired electrons.
Idea: Spin-Only Magnetic Moment
New ideaEasyNumerical value - 11 Apr, Shift 2Q83The number of correct statements from the following is __________. A. For 1s orbital, the probability density is maximum at the nucleus B.…
Idea: Interpreting Radial Probability Curves
New ideaMediumNumerical value - 13 Apr, Shift 2Q83The orbital angular momentum of an electron in 3s orbital is . The value of is ______ (nearest integer)
Idea: Orbital and Spin Angular Momentum
New ideaEasyNumerical value
JEE Main 202214 questions in 14 shifts
- 25 Jul, Shift 1Q62Which of the following sets of quantum numbers is not allowed ?
Idea: Validity of Quantum Number Sets
New ideaEasySingle correct - 27 Jul, Shift 2Q61The correct decreasing order of energy for the orbitals having, following set of quantum numbers : (A) , , (B) ,…
Idea: Aufbau Principle and n+l Rule
Asked the year beforeEasySingle correct - 28 Jul, Shift 1Q61Identify the incorrect statement from the following.
Idea: Magnetic Quantum Number
Asked the year beforeMediumSingle correct - 28 Jul, Shift 2Q38Which of the following pair is not isoelectronic species? (At. no. Sm, 62; Er, 68; Yb, 70; Lu, 71; Eu, 63; Tb, 65; Tm, 69)
Idea: Configurations of Isoelectronic Species
MediumSingle correct - 29 Jul, Shift 2Q62Given below are the quantum numbers for 4 electrons. A. B. C.…
Idea: Aufbau Principle and n+l Rule
Asked the year beforeMediumSingle correct - 24 Jun, Shift 1Q62Consider the following pairs of electrons (A) (a) (b) (B) (a)…
Idea: Hydrogen vs Multi-Electron Degeneracy
New ideaEasyOther - 25 Jun, Shift 1Q63The pair, in which ions are isoelectronic with is :
Idea: Isoelectronic Species Configurations
New ideaEasySingle correct - 26 Jun, Shift 2Q61The number of radial and angular nodes in 4d orbital are, respectively
Idea: Calculation of Radial and Angular Nodes
Asked the year beforeEasySingle correct - 27 Jun, Shift 2Q82Consider the following set of quantum numbers. n l A. 3 3 B. 3 2 C. 2 1 D. 2 2 The number of correct…
Idea: Validity of Quantum Number Sets
New ideaEasyNumerical value - 28 Jun, Shift 1Q63Element “E” belongs to the period 4 and group 16 of the periodic table. The valence shell electron configuration of the element, which is…
Idea: Predicting Periodic Table Position
New ideaEasySingle correct - 28 Jun, Shift 2Q62Consider the following statements : (A) The principal quantum number ‘n’ is a positive integer with values of ‘n’ (B) The…
Idea: Validity of Quantum Number Sets
New ideaEasyOther - 29 Jun, Shift 1Q62Which of the following statements are correct ? (A) The electronic configuration of Cr is [Ar] . (B) The magnetic quantum…
Idea: Anomalous Electron Configurations
New ideaEasyOther - 29 Jun, Shift 2Q62Which of the following is the correct plot for the probability density as a function of distance 'r' of the electron from…
Idea: Interpreting Radial Wavefunction Graphs
New ideaMediumDiagram based · figure - 30 Jun, Shift 1Q62The number of radial nodes and total number of nodes in 4p orbital respectively are :
Idea: Calculation of Radial and Angular Nodes
Asked the year beforeEasySingle correct
JEE Main 202110 questions in 10 shifts
- 27 Aug, Shift 1Q57The number of electrons in the ground state electronic configuration of Np (Z = 93) is __________. (Integer answer)
Idea: Anomalous Configurations of Heavy Metals
New ideaMediumNumerical value - 31 Aug, Shift 1Q52Ge () in its ground state electronic configuration has completely filled orbitals with . The value of…
Idea: Magnetic Quantum Number
Asked the year beforeMediumNumerical value - 31 Aug, Shift 2 · Q53Magnetic Quantum NumberAsked the year beforeEasy
- 25 Feb, Shift 1 · Q31Interpreting Radial Probability Distribution GraphsNew ideaMedium
- 26 Feb, Shift 1 · Q31Calculation of Radial and Angular NodesNew ideaEasy
- 22 Jul, Shift 2 · Q53Aufbau Principle and n+l RuleAsked the year beforeEasy
- 16 Mar, Shift 2 · Q53Magnetic Quantum NumberAsked the year beforeEasy
- 17 Mar, Shift 1 · Q53Calculation of Radial and Angular NodesNew ideaMedium
- 17 Mar, Shift 2 · Q53Counting Unpaired ElectronsNew ideaEasy
- 18 Mar, Shift 1 · Q32Calculation of Radial and Angular NodesNew ideaEasy
JEE Main 20203 questions in 3 shifts
- 2 Sep, Shift 2 · Q30Magnetic Quantum NumberNew ideaMedium
- 3 Sep, Shift 2 · Q30Azimuthal Quantum NumberNew ideaHard
- 5 Sep, Shift 1 · Q33Aufbau Principle and n+l RuleNew ideaEasy
JEE Main 20171 question in 1 shift
Questions from the official JEE Main Paper 1 shifts published by NTA (CBSE for 2017). Questions NTA dropped are left out. Topic and idea tags, counts and notes are Lumi’s.