Periodic Table · JEE Main previous year questions

2026 15 questions

1. Q712026 · 6 Apr 2026 · Shift 1· Numerical answer

   First and second ionization enthalpies of lithium are $520\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$ and $7297\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$ respectively. Energy required to convert $3.5\mathrm{mg}$ lithium (g) into $\mathrm{L}{\mathrm{i}}^{2+}(\mathrm{g})$ [$\mathrm{Li}(\mathrm{g})\to \mathrm{L}{\mathrm{i}}^{2+}(\mathrm{g})$] is ____ $\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$. (nearest integer) [Molar mass of $\mathrm{Li}=7\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$]

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   Answer: 4

2. Q582026 · 6 Apr 2026 · Shift 2

   In a period, the first ionisation enthalpy of the element at extreme left and the negative electron gain enthalpy of the extreme right element, except noble gases, are respectively.

   1. A.lowest and lowest
   2. B.highest and lowest
   3. C.lowest and highest
   4. D.highest and highest
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   Answer: C

3. Q582026 · 4 Apr 2026 · Shift 1

   A monoatomic anion $({\mathrm{A}}^{-})$ has 45 neutrons and 36 electrons. Atomic mass, group in the periodic table and physical state at room temperature of the element $(\mathrm{A})$ respectively are

   1. A.$80,17$, liquid
   2. B.$81,16$, solid
   3. C.$80,16$, gas
   4. D.$81,15$, gas
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   Answer: A

4. Q592026 · 4 Apr 2026 · Shift 1

   Given below are two statements: Statement I: The covalency of oxygen is generally two but it can exceed upto four. The oxidation state of oxygen in $\mathrm{S}{\mathrm{O}}_2$ is $-2$ and in $\mathrm{O}{\mathrm{F}}_2$ it is $+2$. Statement II: The anomalous behaviour of oxygen when compared to the other elements of group 16 is due to its small size and high electronegativity. 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 true
   2. B.Both Statement I and Statement II are false
   3. C.Statement I is true but Statement II is false
   4. D.Statement I is false but Statement II is true
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   Answer: A

5. Q522026 · 2 Apr 2026 · Shift 1

   What is the energy (in $\mathrm{J}\mathrm{ato}{\mathrm{m}}^{-1}$) required for the following process ? $$\mathrm{L}{\mathrm{i}}^{2+}(\mathrm{g})\to \mathrm{L}{\mathrm{i}}^{3+}(\mathrm{g})+{\mathrm{e}}^{-}$$ (Take the ionization energy for the H atom in the ground state as $2.18\times 10^{-18}\mathrm{J}\mathrm{ato}{\mathrm{m}}^{-1}$)

   1. A.$8.72\times 10^{-18}$
   2. B.$1.962\times 10^{-18}$
   3. C.$1.962\times 10^{-17}$
   4. D.$6.54\times 10^{-17}$
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   Answer: C

6. Q532026 · 28 Jan 2026 · Shift 1

   In period 4 of the periodic table, the elements with highest and lowest atomic radii are respectively.

   1. A.$\mathrm{Rb}$ & $\mathrm{Br}$
   2. B.$\mathrm{Na}$ & $\mathrm{Cl}$
   3. C.$\mathrm{K}\&\mathrm{Br}$
   4. D.$\mathrm{K}\&\mathrm{Se}$
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   Answer: C

7. Q622026 · 28 Jan 2026 · Shift 2

   Consider the elements N, P, O, S, Cl and F. The number of valence electrons present in the elements with most and least metallic character from the above list is respectively.

   1. A.7 and 5
   2. B.6 and 7
   3. C.5 and 7
   4. D.5 and 6
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   Answer: C

8. Q582026 · 24 Jan 2026 · Shift 1

   Given below are two statements : Statement I : $\mathrm{K}>\mathrm{Mg}>\mathrm{Al}>\mathrm{B}$ is the correct order in terms of metallic character. Statement II : Atomic radius is always greater than the ionic radius for any element. 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.Statement I is false but Statement II is true
   3. C.Statement I is true but Statement II is false
   4. D.Both Statement I and Statement II are true
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   Answer: C

9. Q582026 · 23 Jan 2026 · Shift 1

   The correct trend in the first ionization enthalpies of the elements in the $3^{\mathrm{rd}}$ period of periodic table is :

   1. A.$\mathrm{Si}<\mathrm{S}<\mathrm{Al}<\mathrm{P}<\mathrm{Cl}$
   2. B.$\mathrm{Al}<\mathrm{Si}<\mathrm{S}<\mathrm{P}<\mathrm{Cl}$
   3. C.$\mathrm{S}<\mathrm{Si}<\mathrm{Al}<\mathrm{P}<\mathrm{Cl}$
   4. D.$\mathrm{Al}<\mathrm{S}<\mathrm{P}<\mathrm{Si}<\mathrm{Cl}$
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   Answer: B

10. Q592026 · 23 Jan 2026 · Shift 1

    The correct statements from the following are : A. Ionic radii of trivalent cations of group 13 elements decreases down the group. B. Electronegativity of group 13 elements decreases down the group. C. Among the group 13 elements, Boron has highest first ionisation enthalpy. D. The trichloride and triiodide of group 13 elements are covalent in nature. Choose the correct answer from the options given below :

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

11. Q632026 · 23 Jan 2026 · Shift 2

    Given below are two statements : Statement I : The second ionisation enthalpy of Na is larger than the corresponding ionisation enthalpy of Mg . Statement II : The ionic radius of ${\text{O}}^{2-}$ is larger than that of ${\text{F}}^{-}$. In the light of the above statements, choose the correct answer from the options given below :

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

12. Q702026 · 23 Jan 2026 · Shift 2

    Elements X and Y belong to Group 15. The difference between the electronegativity values of ' X ' and phosphorus is higher than that of the difference between phosphorus and ' Y '. ' X ' & ' Y ' are respectively

    1. A.As & Bi
    2. B.Bi & N
    3. C.N & As
    4. D.As & Sb
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    Answer: C

13. Q612026 · 22 Jan 2026 · Shift 1

    A 'p'-block element $(\mathrm{E})$ and hydrogen form a binary cation $(\mathrm{E}{\mathrm{H}}_{\mathrm{x}}{)}^{+}$, while $\mathrm{E}{\mathrm{H}}_3$ on treatment with ${\mathrm{K}}_2\mathrm{Hg}{\mathrm{I}}_4$ in alkaline medium gives a precipitate of basic mercury(II)amido-iodine. Given below are first ionisation enthalpy values $\left(\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}\right)$ for first element each from group 13, 14, 15 and 16. Identify the correct first ionisation enthalpy value for element E.

    1. A.1402
    2. B.1086
    3. C.801
    4. D.1312
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    Answer: A

14. Q652026 · 21 Jan 2026 · Shift 1

    Which of the following represents the correct trend for the mentioned property? A. F > P > S > B - First Ionization Energy B. Cl > F > S > P - Electron Affinity C. K > Al > Mg > B - Metallic character D. ${\mathrm{K}}_2\mathrm{O}>\mathrm{N}{\mathrm{a}}_2\mathrm{O}>\mathrm{MgO}>\mathrm{A}{\mathrm{l}}_2{\mathrm{O}}_3$ - Basic character Choose the correct answer from the options given below :

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

15. Q592026 · 21 Jan 2026 · Shift 2

    Given below are two statements : Statement I : The correct order in terms of atomic/ionic radii is Al > Mg > $\mathrm{M}{\mathrm{g}}^{2+}$ > $\mathrm{A}{\mathrm{l}}^{3+}$. Statement II : The correct order in terms of the magnitude of electron gain enthalpy is Cl > Br > S > O. In the light of the above statements, choose the correct answer from the options given below :

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