JEE Main · Chemistry · Coordination Compounds

Coordination Nomenclature: JEE Main previous year questions

Name: Coordination Nomenclature: JEE Main previous year questions
Creator: Lumi

10 questions in the 108 JEE Main shifts Lumi analysed, in 5 of 8 years. Pattern: Asked most years. 2 came in 2024–26. Here is how it is asked and which ideas come back.

Questions: 10; in 10 of 108 shifts
Years asked: 5/8; last asked 2024
Chance in a shift: 9%; calibrated model, how we compute it
Weighted estimate: 0.1; model; history: 0.1 a shift on average, typically 0.0–0.1

Key findings

01
Asked in 5 of 8 years with analysed shifts and in 10 of 108 shifts: 10 questions, #177 of 196 topics. Last asked in 2024.
02
40% of its questions since 2020 tested an idea no earlier year had asked; 5 repeated an idea from the year before.
03
The most repeated idea is Oxidation State Calculation, asked 7 times in 7 shifts (2020, 2021, 2022, 2024), most often as “oxidation states in coordination compounds”.
04
JEE Main has asked 4 of the 49 ideas in this topic; 41 have never been asked, directly or inside another question.
05
Mostly asked as single correct (70%); 30% need a numerical answer, 50% are easy and 10% hard.
06
The skill tested most is calculation (40%), then multi-step (30%).

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: 0 in 1 shift · 2020: 2 in 12 shifts · 2021: 3 in 24 shifts · 2022: 2 in 24 shifts · 2023: 1 in 12 shifts · 2024: 2 in 18 shifts · 2025: 0 in 8 shifts · 2026: 0 in 9 shifts.

Up to 2023: 0.1; a shift, of 25
Since 2024: 0.0; -0.1
Usual gap: 1.0 yrs; between years asking it
Shifts with it: 10/108; 9% of analysed shifts

How it is asked

Difficulty, format and skill

Across all 10 questions on Coordination Nomenclature since 2017.

Difficulty

QUESTIONS

541

Easy5 · 50%
Medium4 · 40%
Hard1 · 10%

Format

Single correct · 7 Q70%
Numerical value · 3 Q30%

Skill tested

Calculation · 4 Q40%
Multi-step · 3 Q30%
Recall · 2 Q20%
Application · 1 Q10%

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.

’17’20’21’22’23’24’25’26

Idea asked for the first time
Idea asked in an earlier year

Coverage of the topic

JEE Main has asked 4 of the 49 ideas in this topic. 41 have never been asked yet.

Asked directly4 · 8%
Touched inside another question4 · 8%
Never asked41 · 84%

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

Idea, year, question

Every idea JEE Main tested in this topic, with its eight years. Open one to read the questions.

ideaAskedShareYears’17’20’21’22’23’24’25’26

OpenRepeated7 · 70%70%4/832
- 8 Apr ’24 S1 · Q70
  An octahedral complex with the formula $\mathrm{CoCl_3\cdot nNH_3}$ upon reaction with excess of $\mathrm{AgNO_3}$ solution gives 2 moles…
  mediumSingle correct
- 29 Jul ’22 S2 · Q86
  Sum of oxidation state (magnitude) and coordination number of cobalt in $\mathrm{Na[Co(bpy)Cl_4]}$ is ____. (Given: bpy = [figure:…
  easyNumerical valueAsked the year before
- 30 Jul ’22 S2 · Q50
  In the ring test of $\mathrm{NO_3^-}$ ion what is the oxidation number of iron in the complex (brown ring)…
  mediumSingle correctAsked the year before
- 3 Aug ’21 S2 · Q40
  The oxidation states of Fe in $\mathrm{[Fe(NCS)(NH_3)_5]SO_4}$ , $\mathrm{Na_3[Fe(S_2O_3)_3]}$ and $\mathrm{[Fe(CO)_5]}$ respectively are
  easySingle correctAsked the year before
- 4 Aug ’21 S1 · Q57
  Among the following species, the number of species with oxidation state of Fe in +3 is ________. A.…
  mediumNumerical valueAsked the year before
- 4 Aug ’21 S2 · Q38
  The oxidation states of Mn in $\mathrm{Mn_2(CO)_{10}}$ , $\left[\mathrm{Mn(CO)_5Br}\right]$ and $\mathrm{K}\left[\mathrm{Mn(CN)_6}\right]$ …
  easySingle correctAsked the year before
- 2 Sep ’20 S1 · Q49
  The oxidation states of iron atoms in compounds (A), (B) and (C), respectively, are $x$ , $y$ and $z$ . The sum of $x$ , $y$ and $z$ is…
  mediumNumerical valueNew idea
Open1 · 10%10%1/8
Open1 · 10%10%1/8
Open1 · 10%10%1/8

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

4 different ideas were tested; 1 came more than once.

Oxidation State Calculation7×
oxidation states in coordination compounds
Single correct · 7 shifts · 3 numerical
Complex Numerical Prefixes (Bis/Tris)1×
iupac name of coordination complex
Single correct · 1 shift
Anionic Complex Suffixes1×
iupac name of coordination compound
Single correct · 1 shift
IUPAC Ligand Naming1×
iupac name of complex from magnetic moment and reactivity
Single correct · 1 shift

Idea	Times	Shifts	Format	Numerical
Oxidation State Calculationoxidation states in coordination compounds	7	7	Single correctCalculation	3
Complex Numerical Prefixes (Bis/Tris)iupac name of coordination complex	1	1	Single correctRecall	–
Anionic Complex Suffixesiupac name of coordination compound	1	1	Single correctRecall	–
IUPAC Ligand Namingiupac name of complex from magnetic moment and reactivity	1	1	Single correctMulti-step	–

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

Coordination Nomenclature questions, year by year

The opening words of each question as it appeared in the official paper, with the idea it tested. Open one for its options and the official answer.

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.

Key findings

Questions a shift, year by year

Difficulty, format and skill

Difficulty

Format

Skill tested

New idea, or one asked before?

Coverage of the topic

Idea, year, question

Every idea inside this topic

Coordination Nomenclature questions, year by year

JEE Main 20242 questions in 2 shifts

JEE Main 20231 question in 1 shift

JEE Main 20222 questions in 2 shifts

JEE Main 20213 questions in 3 shifts

JEE Main 20202 questions in 2 shifts

More topics in Coordination Compounds