Atomic Structure · JEE Main previous year questions

2026 25 questions

1. Q582026 · 8 Apr 2026 · Shift 2

   Match List - I with List - II. $$\begin{array}{ll}\text{List - I}& \text{List - II}\\ \text{Electronic configuration of neutral atom (where }n=2)& 1^{\mathrm{st}}\text{Ionization Energy}(\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1})\\ \text{A. }\mathrm{n}{\mathrm{s}}^2& \text{I. }2080\\ \text{B. }\mathrm{n}{\mathrm{s}}^2\mathrm{n}{\mathrm{p}}^1& \text{II. }899\\ \text{C. }\mathrm{n}{\mathrm{s}}^2\mathrm{n}{\mathrm{p}}^3& \text{III. }800\\ \text{D. }\mathrm{n}{\mathrm{s}}^2\mathrm{n}{\mathrm{p}}^6& \text{IV. }1402\end{array}$$ Choose the correct answer from the options given below :

   1. A.A-II, B-III, C-IV, D-I
   2. B.A-IV, B-III, C-II, D-I
   3. C.A-III, B-II, C-IV, D-I
   4. D.A-III, B-II, C-I, D-IV
   Show answer

   Answer: A

2. Q532026 · 6 Apr 2026 · Shift 1

   Match the LIST-I with LIST-II $$\begin{array}{llll}\text{List-I}& & \text{List-II}& \\ \text{Orbital}& & \text{Radial nodes and nodal plane}& \\ \text{A.}& \text{2s}& \text{I.}& \text{1 Radial node + two nodal planes}\\ \text{B.}& \text{3s}& \text{II.}& \text{1 Radial node + one nodal plane}\\ \text{C.}& \text{3p}& \text{III.}& \text{2 Radial nodes + No nodal plane}\\ \text{D.}& \text{4d}& \text{IV.}& \text{1 Radial node + No nodal plane}\end{array}$$ Choose the correct answer from the options given below:

   1. A.A-IV, B-I, C-III, D-II
   2. B.A-IV, B-II, C-III, D-I
   3. C.A-III, B-I, C-IV, D-II
   4. D.A-IV, B-III, C-II, D-I
   Show answer

   Answer: D

3. Q602026 · 6 Apr 2026 · Shift 1

   The correct statements among the following are. A. Basic vanadium oxide is used in the manufacture of ${\mathrm{H}}_2\mathrm{S}{\mathrm{O}}_4$. B. The spin-only magnetic moment value of the transition metal halide employed in Ziegler-Natta polymerization is 2.84 BM. C. The p-block metal compound employed in Ziegler-Natta polymerization has the metal in +3 oxidation state. D. The number of electrons present in the outer most 'd' orbital of metal halide employed in Wacker process is 8. Choose the correct answer from the options given below:

   1. A.A and B Only
   2. B.A, C and D Only
   3. C.C and D Only
   4. D.B, C and D Only
   Show answer

   Answer: C

4. Q622026 · 6 Apr 2026 · Shift 1

   Which of the following are true about the energy of the given d-orbitals of a tetrahedral complex? A. ${\mathrm{d}}_{xy}={\mathrm{d}}_{xz}>{\mathrm{d}}_{x^2-y^2}$ B. ${\mathrm{d}}_{xy}={\mathrm{d}}_{yz}>{\mathrm{d}}_{z^2}$ C. ${\mathrm{d}}_{x^2-y^2}>{\mathrm{d}}_{z^2}>{\mathrm{d}}_{xz}$ D. ${\mathrm{d}}_{x^2-y^2}={\mathrm{d}}_{z^2}<{\mathrm{d}}_{xz}$ Choose the correct answer from the given below:

   1. A.A, B and D only
   2. B.A and B only
   3. C.B and D only
   4. D.B, C and D only
   Show answer

   Answer: A

5. Q522026 · 6 Apr 2026 · Shift 2

   The Bohr radius of a hydrogen like species is $70.53\text{ pm}$. The species and the stationary state (n) are respectively (Given : Hydrogen atom Bohr radius is $52.9\text{ pm}$)

   1. A.${\text{Li}}^{2+},3$
   2. B.${\text{He}}^{+},3$
   3. C.${\text{He}}^{+},2$
   4. D.${\text{Li}}^{2+},2$
   Show answer

   Answer: D

6. Q522026 · 5 Apr 2026 · Shift 1

   Arrange the following atomic orbitals of multi electron atoms in order of increasing energy. A. $n=3,l=2,m=+1$ B. $n=4,l=0,m=0$ C. $n=6,l=1,m=0$ D. $n=5,l=1,m=+1$ E. $n=2,l=1,m=+1$ Choose the correct answer from the options given below:

   1. A.$\text{C}<\text{D}<\text{B}<\text{A}<\text{E}$
   2. B.$\text{B}<\text{A}<\text{E}<\text{C}<\text{D}$
   3. C.$\text{E}<\text{C}<\text{D}<\text{B}<\text{A}$
   4. D.$\text{E}<\text{B}<\text{A}<\text{D}<\text{C}$
   Show answer

   Answer: D

7. Q532026 · 5 Apr 2026 · Shift 1

   Identify the correct statements from the following : A. Heisenberg uncertainty principle is applicable to electrons. B. The size of $2{\text{p}}_x$ orbital is less than the size of $3{\text{p}}_x$ orbital. C. The energy of $2\text{s}$ orbital of $\text{H}$ atom is equal to the energy of $2\text{s}$ orbital of $\text{Li}$. D. The electronic configuration of $\text{Cr}$ is $[\text{Ar}]3{\text{d}}^{5}4{\text{s}}^1$ Choose the correct answer from the options given below:

   1. A.A, B and C Only
   2. B.A, B and D Only
   3. C.B, C and D Only
   4. D.A, C and D Only
   Show answer

   Answer: B

8. Q592026 · 5 Apr 2026 · Shift 1

   Correct statements from the following are: A. Nitrogen in oxidation states from $+1$ to $+4$ disproportionates in acid medium. B. Nitrogen has the ability to form $\text{d}\pi \text{ - p}\pi$ multiple bonds with itself and other elements with small size and high electronegativity. C. $\text{N-N}$ single bond is stronger than $\text{P-P}$ single bond. D. Nitrogen has highest density in its group due to small size. E. The maximum covalency of nitrogen is four since it has only four valence orbitals for bonding. Choose the correct answer from the options given below:

   1. A.B, C and D Only
   2. B.C, D and E Only
   3. C.A, C and E Only
   4. D.A and E Only
   Show answer

   Answer: D

9. Q522026 · 5 Apr 2026 · Shift 2

   Which of the following statement(s) is/are $\underline{\text{true}}$ ? A. If two orbitals have the same value of $(n+l)$, the orbital with lower value of $n$ will have lower energy. B. Energies of the orbitals in the same subshell increase with increase in atomic number. C. The size of $2{\mathrm{p}}_x$ orbital is less than the size of $3{\mathrm{p}}_x$ orbital. D. Among $5\mathrm{f}$, $6\mathrm{s}$, $4\mathrm{d}$, $5\mathrm{p}$ and $5\mathrm{d}$ orbitals, none of the orbitals have $2$ radial nodes. Choose the $\underline{\text{correct}}$ answer from the options given below :

   1. A.A, B and C only
   2. B.A and C only
   3. C.C and D only
   4. D.A only
   Show answer

   Answer: B

10. Q532026 · 4 Apr 2026 · Shift 1

    Which of the following is correct set of 4 quantum numbers of $19^{\text{th}}$ electron in Chromium (Atomic number $=24$) in accordance with Aufbau principle?

    1. A.$n=3,l=2,m=+2,s=+\frac{1}{2}$
    2. B.$n=3,l=2,m=-2,s=+\frac{1}{2}$
    3. C.$n=4,l=1,m=0,s=+\frac{1}{2}$
    4. D.$n=4,l=0,m=0,s=+\frac{1}{2}$
    Show answer

    Answer: D

11. Q522026 · 4 Apr 2026 · Shift 2

    The species having identical radii according to the Bohr's theory are: A. $\mathrm{H}$ (first orbit) B. $\mathrm{H}{\mathrm{e}}^{+}$ (first orbit) C. $\mathrm{H}{\mathrm{e}}^{+}$ (Second orbit) D. $\mathrm{L}{\mathrm{i}}^{2+}$ (first orbit) E. $\mathrm{B}{\mathrm{e}}^{3+}$ (Second orbit) Choose the correct answer from the options given below:

    1. A.A and C Only
    2. B.A and E Only
    3. C.B and E Only
    4. D.C and D Only
    Show answer

    Answer: B

12. Q532026 · 4 Apr 2026 · Shift 2
    
    1. A.
    2. B.
    3. C.
    4. D.
    Show answer

    Answer: C

13. Q592026 · 4 Apr 2026 · Shift 2

    Pairs of elements with the same number of electrons in their respective 4f orbital are [Atomic number: Eu-63, Gd-64, Dy-66, Ho-67, Tm-69, Yb-70, Lu-71, Hf-72] A. (Eu and Gd) B. (Dy and Ho) C. (Yb and Hf) D. (Lu and Tm) Choose the correct answer from the options given below:

    1. A.B and C Only
    2. B.A and B Only
    3. C.A and D Only
    4. D.A and C Only
    Show answer

    Answer: D

14. Q612026 · 28 Jan 2026 · Shift 1

    The wave numbers of three spectral lines of H atom are considered. Identify the set of spectral lines belonging to Balmer series. ( $R=$ Rydberg constant)

    1. A.$\frac{5R}{36}$, $\frac{3R}{16}$, $\frac{21R}{100}$
    2. B.$\frac{7R}{144}$, $\frac{3R}{16}$, $\frac{16R}{255}$
    3. C.$\frac{3R}{4}$, $\frac{3R}{16}$, $\frac{7R}{144}$
    4. D.$\frac{5R}{36}$, $\frac{8R}{9}$, $\frac{15R}{16}$
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    Answer: A

15. Q642026 · 28 Jan 2026 · Shift 1
    
    1. A.D
    2. B.B
    3. C.C
    4. D.A
    Show answer

    Answer: B

16. Q592026 · 28 Jan 2026 · Shift 2

    The wavelength of photon 'A' is 400 nm. The frequency of photon 'B' is $10^{16}{\text{ s}}^{-1}$. The wave number of photon 'C' is $10^4{\text{ cm}}^{-1}$. The correct order of energy of these photons is :

    1. A.$\text{A}>\text{C}>\text{B}$
    2. B.$\text{C}>\text{B}>\text{A}$
    3. C.$\text{B}>\text{A}>\text{C}$
    4. D.$\text{A}>\text{B}>\text{C}$
    Show answer

    Answer: C

17. Q712026 · 28 Jan 2026 · Shift 2· Numerical answer

    The number of isoelectronic species among $S{c}^{3+},C{r}^{2+},M{n}^{3+},C{o}^{3+}$ and $F{e}^{3+}$ is 'n'. If 'n' moles of AgCl is formed during the reaction of complex with formula $CoC{l}_3(en{)}_{2}N{H}_3$ with excess of $AgN{O}_3$ solution, then the number of electrons present in the $t_{2g}$ orbital of the complex is ________.

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    Answer: 6

18. Q742026 · 28 Jan 2026 · Shift 2· Numerical answer
    
    Show answer

    Answer: 2

19. Q712026 · 24 Jan 2026 · Shift 1· Numerical answer

    The hydrogen spectrum consists of several spectral lines in Lyman series ($L_1,L_2,L_3\dots ;{\mathrm{L}}_1$ has lowest energy among Lyman series). Similarly it consists of several spectral lines in Balmer series (${\mathrm{B}}_1,{\mathrm{B}}_2,{\mathrm{B}}_3\dots ;{\mathrm{B}}_1$ has lowest energy among Balmer lines). The energy of $L_1$ is $x$ times the energy of $B_1$. The value of $x$ is ____ $\times 10^{-1}$. (Nearest integer)

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    Answer: 54

20. Q572026 · 23 Jan 2026 · Shift 1

    Given, (A) $n=5,m_l=-1$ (B) $n=3,l=2,m_l=-1,m_s=+\frac{1}{2}$ The maximum number of electron(s) in an atom that can have the quantum numbers as given in (A) and (B) respectively are :

    1. A.4 and 1
    2. B.2 and 4
    3. C.26 and 1
    4. D.8 and 1
    Show answer

    Answer: D

21. Q692026 · 23 Jan 2026 · Shift 1

    Given below are two statements : Statement I : $[{\mathrm{CoBr}}_4{]}^{2-}$ ion will absorb light of lower energy than $[{\mathrm{CoCl}}_4{]}^{2-}$ ion. Statement II : In $[{\mathrm{CoI}}_4{]}^{2-}$ ion, the energy separation between the two set of d-orbitals is more than $[{\mathrm{CoCl}}_4{]}^{2-}$ ion. In the light of the above statements, choose the correct answer from the options given below :

    1. A.Both Statement I and Statement II are false
    2. B.Both Statement I and Statement II are true
    3. C.Statement I is false but Statement II is true
    4. D.Statement I is true but Statement II is false
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    Answer: D

22. Q582026 · 23 Jan 2026 · Shift 2

    The work functions of two metals (${\text{M}}_{\text{A}}$ and ${\text{M}}_{\text{B}}$) are in the $1:2$ ratio. When these metals are exposed to photons of energy $6\text{ eV}$ , the kinetic energy of liberated electrons of $M_A:M_B$ is in the ratio of $2.642:1$. The work functions (in $\text{eV}$ ) of $M_A$ and $M_B$ are respectively.

    1. A.3.1, 6.2
    2. B.1.5, 3.0
    3. C.2.3, 4.6
    4. D.1.4, 2.8
    Show answer

    Answer: C

23. Q552026 · 22 Jan 2026 · Shift 1

    As compared with chlorocyclohexane, which of the following statements correctly apply to chlorobenzene? A. The magnitude of negative charge is more on chlorine atom. B. The $\mathrm{C}-\mathrm{Cl}$ bond has partial double bond character. C. $\mathrm{C}-\mathrm{Cl}$ bond is less polar. D. $\mathrm{C}-\mathrm{Cl}$ bond is longer due to repulsion between delocalised electrons of the aromatic ring and lone pairs of electrons of chlorine. E. The $\mathrm{C}-\mathrm{Cl}$ bond is formed using $\mathrm{s}{\mathrm{p}}^2$ hybridised orbital of carbon. Choose the correct answer from the options given below :

    1. A.B, C and E Only
    2. B.A, C and E Only
    3. C.B, C and D Only
    4. D.A, D and E Only
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    Answer: A

24. Q572026 · 22 Jan 2026 · Shift 1

    The energy required by electrons, present in the first Bohr orbit of hydrogen atom to be excited to second Bohr orbit is ____ $\mathrm{J}\mathrm{mo}{\mathrm{l}}^{-1}$. Given: $R_H=2.18\times 10^{-11}\mathrm{ergs}$.

    1. A.$9.835\times 10^{12}$
    2. B.$1.635\times 10^{-11}$
    3. C.$1.635\times 10^{-18}$
    4. D.$9.835\times 10^5$
    Show answer

    Answer: D

25. Q592026 · 22 Jan 2026 · Shift 1

    Consider the transition metal ions $\mathrm{M}{\mathrm{n}}^{3+},\mathrm{C}{\mathrm{r}}^{3+},\mathrm{F}{\mathrm{e}}^{3+}$ and $\mathrm{C}{\mathrm{o}}^{3+}$ and all form low spin octahedral complexes. The correct decreasing order of unpaired electrons in their respective d-orbitals of the complexes is

    1. A.$\mathrm{C}{\mathrm{r}}^{3+}>\mathrm{M}{\mathrm{n}}^{3+}>\mathrm{F}{\mathrm{e}}^{3+}>\mathrm{C}{\mathrm{o}}^{3+}$
    2. B.$\mathrm{M}{\mathrm{n}}^{3+}>\mathrm{F}{\mathrm{e}}^{3+}>\mathrm{C}{\mathrm{o}}^{3+}>\mathrm{C}{\mathrm{r}}^{3+}$
    3. C.$\mathrm{F}{\mathrm{e}}^{3+}>\mathrm{C}{\mathrm{o}}^{3+}>\mathrm{M}{\mathrm{n}}^{3+}>\mathrm{C}{\mathrm{r}}^{3+}$
    4. D.$\mathrm{C}{\mathrm{r}}^{3+}>\mathrm{F}{\mathrm{e}}^{3+}>\mathrm{C}{\mathrm{o}}^{3+}>\mathrm{M}{\mathrm{n}}^{3+}$
    Show answer

    Answer: A