Atomic Structure · JEE Main previous year questions

2022 17 questions

1. Q822022 · 29 Jul 2022 · Shift 1· Numerical answer

   The minimum uncertainty in the speed of an electron in an one dimensional region of length $2{\mathrm{a}}_0$ (Where ${\mathrm{a}}_0=\text{Bohr radius }52.9\mathrm{pm}$) is ________ $\mathrm{km}{\mathrm{s}}^{-1}$. (Given : Mass of electron $=9.1\times 10^{-31}\mathrm{kg}$, Planck's constant $\mathrm{h}=6.63\times 10^{-34}\mathrm{Js}$)

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   Answer: 548

2. Q622022 · 29 Jul 2022 · Shift 2

   Given below are the quantum numbers for 4 electrons. A. $n=3,l=2,m_l=1,m_s=+1/2$ B. $n=4,l=1,m_l=0,m_s=+1/2$ C. $n=4,l=2,m_l=-2,m_s=-1/2$ D. $n=3,l=1,m_l=-1,m_s=+1/2$ The correct order of increasing energy is :

   1. A.$D<B<A<C$
   2. B.$D<A<B<C$
   3. C.$B<D<A<C$
   4. D.$B<D<C<A$
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   Answer: B

3. Q612022 · 28 Jul 2022 · Shift 2

   Given below are two statements: One is labelled as Assertion $\mathbf{A}$ and the other is labelled as Reason $\mathbf{R}$ Assertion $\mathbf{A}$ : Zero orbital overlap is an out of phase overlap. Reason $\mathbf{R}$ : It results due to different orientation / direction of approach of orbitals. In the light of the above statements, choose the correct answer from the options given below

   1. A.Both A and R are true and R is the correct explanation of A
   2. B.Both A and R are true but R is NOT the correct explanation of A
   3. C.A is true but R is false
   4. D.A is false but R is true
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   Answer: A

4. Q632022 · 27 Jul 2022 · Shift 1

   Given below are two statements. One is labelled as Assertion A and the other is labelled as Reason R. Assertion A: Energy of $2s$ orbital of hydrogen atom is greater than that of $2s$ orbital of lithium. Reason R: Energies of the orbitals in the same subshell decrease with increase in the atomic number. In the light of the above statements, choose the correct answer from the options given below.

   1. A.Both A and R are true and R is the correct explanation of A.
   2. B.Both A and R are true but R is NOT the correct explanation of A.
   3. C.A is true but R is false.
   4. D.A is false but R is true.
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   Answer: A

5. Q612022 · 27 Jul 2022 · Shift 2

   The correct decreasing order of energy for the orbitals having, following set of quantum numbers : (A) $n=3,l=0,m=0$ (B) $n=4,l=0,m=0$ (C) $n=3,l=1,m=0$ (D) $n=3,l=2,m=1$ is :

   1. A.(D) > (B) > (C) > (A)
   2. B.(B) > (D) > (C) > (A)
   3. C.(C) > (B) > (D) > (A)
   4. D.(B) > (C) > (D) > (A)
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   Answer: A

6. Q622022 · 27 Jul 2022 · Shift 2

   Match List - I with List - II. $$\begin{array}{llll}& \text{List - I}& & \text{List - II}\\ \text{(A)}& {\psi }_{\mathrm{MO}}={\psi }_{\mathrm{A}}-{\psi }_{\mathrm{B}}& \text{(I)}& \text{Dipole moment}\\ \text{(B)}& \mu =Q\times r& \text{(II)}& \text{Bonding molecular orbital}\\ \text{(C)}& \frac{N_{\mathrm{b}}-N_{\mathrm{a}}}{2}& \text{(III)}& \text{Anti-bonding molecular orbital}\\ \text{(D)}& {\psi }_{\mathrm{MO}}={\psi }_{\mathrm{A}}+{\psi }_{\mathrm{B}}& \text{(IV)}& \text{Bond order}\end{array}$$ Choose the correct answer from the options given below :

   1. A.(A) – (II), (B) – (I), (C) – (IV), (D) – (III)
   2. B.(A) – (III), (B) – (IV), (C) – (I), (D) – (II)
   3. C.(A) – (III), (B) – (I), (C) – (IV), (D) – (II)
   4. D.(A) – (III), (B) – (IV), (C) – (II), (D) – (I)
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   Answer: C

7. Q652022 · 27 Jul 2022 · Shift 2

   Outermost electronic configurations of four elements A, B, C, D are given below : (A) $3s^2$ (B) $3s^{2}3p^1$ (C) $3s^{2}3p^3$ (D) $3s^{2}3p^4$ The correct order of first ionization enthalpy for them is :

   1. A.(A) < (B) < (C) < (D)
   2. B.(B) < (A) < (D) < (C)
   3. C.(B) < (D) < (A) < (C)
   4. D.(B) < (A) < (C) < (D)
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   Answer: B

8. Q612022 · 30 Jun 2022 · Shift 1

   The number of radial nodes and total number of nodes in 4p orbital respectively are :

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

9. Q622022 · 28 Jun 2022 · Shift 2

   Consider the following statements : (A) The principal quantum number 'n' is a positive integer with values of 'n' = 1, 2, 3, ... (B) The azimuthal quantum number 'l' for a given 'n' (principal quantum number) can have values as 'l' = 0, 1, 2, ...... n (C) Magnetic orbital quantum number '${\mathrm{m}}_{\mathrm{l}}$' for a particular 'l' (azimuthal quantum number) has $(2\mathrm{l}+1)$ values. (D) $\pm 1/2$ are the two possible orientations of electron spin. (E) For l = 5, there will be a total of 9 orbital Which of the above statements are correct?

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

10. Q812022 · 27 Jun 2022 · Shift 1· Numerical answer

    If the uncertainty in velocity and position of a minute particle in space are, $2.4\times 10^{-26}(\mathrm{m}{\mathrm{s}}^{-1})$ and $10^{-7}(\mathrm{m})$ respectively. The mass of the particle in $\mathrm{g}$ is ____. (Nearest integer) (Given : $\mathrm{h}=6.626\times 10^{-34}\mathrm{Js}$)

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    Answer: 22

11. Q662022 · 27 Jun 2022 · Shift 2

    The 'f' orbitals are half and completely filled, respectively in lanthanide ions : [Given : Atomic no. $\text{Eu},63;\text{Sm},62;\text{Tm},69;\text{Tb},65;\text{Yb},70;\text{Dy},66$]

    1. A.${\text{Eu}}^{2+}$ and ${\text{Tm}}^{2+}$
    2. B.${\text{Sm}}^{2+}$ and ${\text{Tm}}^{3+}$
    3. C.${\text{Tb}}^{4+}$ and ${\text{Yb}}^{2+}$
    4. D.${\text{Dy}}^{3+}$ and ${\text{Yb}}^{3+}$
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    Answer: C

12. Q822022 · 27 Jun 2022 · Shift 2· Numerical answer

    Consider the following set of quantum numbers. | | $\text{n}$ | $\text{l}$ | ${\text{m}}_l$ | |---|---|---|---| | A. | 3 | 3 | $-3$ | | B. | 3 | 2 | $-2$ | | C. | 2 | 1 | $+1$ | | D. | 2 | 2 | $+2$ | The number of correct sets of quantum numbers is ________.

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    Answer: 2

13. Q622022 · 26 Jun 2022 · Shift 1

    If the radius of the $3^{\mathrm{rd}}$ Bohr's orbit of hydrogen atom is $r_3$ and the radius of $4^{\mathrm{th}}$ Bohr's orbit is $r_4$. Then :

    1. A.$r_4=\frac{9}{16}{r}_3$
    2. B.$r_4=\frac{16}{9}{r}_3$
    3. C.$r_4=\frac{3}{4}{r}_3$
    4. D.$r_4=\frac{4}{3}{r}_3$
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    Answer: B

14. Q612022 · 26 Jun 2022 · Shift 2

    The number of radial and angular nodes in 4d orbital are, respectively

    1. A.1 and 2
    2. B.3 and 2
    3. C.1 and 0
    4. D.2 and 1
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    Answer: A

15. Q882022 · 26 Jun 2022 · Shift 2· Numerical answer

    Reaction of $[\mathrm{Co}({\mathrm{H}}_2\mathrm{O}{)}_6{]}^{2+}$ with excess ammonia and in the presence of oxygen results into a diamagnetic product. Number of electrons present in ${\mathrm{t}}_{2g}$-orbitals of the product is ____.

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    Answer: 6

16. Q612022 · 25 Jun 2022 · Shift 2

    The minimum energy that must be possessed by photons in order to produce the photoelectric effect with platinum metal is : [Given : The threshold frequency of platinum is $1.3\times 10^{15}{\mathrm{s}}^{-1}$ and $\mathrm{h}=6.6\times 10^{-34}\mathrm{J}\mathrm{s}$.]

    1. A.$3.21\times 10^{-14}\mathrm{J}$
    2. B.$6.24\times 10^{-16}\mathrm{J}$
    3. C.$8.58\times 10^{-19}\mathrm{J}$
    4. D.$9.76\times 10^{-20}\mathrm{J}$
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    Answer: C

17. Q852022 · 25 Jun 2022 · Shift 2· Numerical answer

    Amongst $\mathrm{FeC}{\mathrm{l}}_3\cdot 3{\mathrm{H}}_2\mathrm{O}$, ${\mathrm{K}}_3[\mathrm{Fe}(\mathrm{CN}{)}_6]$ and $[\mathrm{Co}(\mathrm{N}{\mathrm{H}}_3{)}_6]\mathrm{C}{\mathrm{l}}_3$, the spin-only magnetic moment value of the inner-orbital complex that absorbs light at shortest wavelength is ____ $B.M.$ [nearest integer]

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    Answer: 2