Atomic Structure · JEE Main previous year questions

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)

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)

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)

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

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)

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 : $\mathrm{h}=6.626\times 10^{-34}\mathrm{Js}$)

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 ${\text{Yb}}^{3+}$

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 ________.

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.$r_4=\frac{4}{3}{r}_3$

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

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 ____.

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.$9.76\times 10^{-20}\mathrm{J}$

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]

Identify the element for which electronic configuration in +3 oxidation state is $[\mathrm{Ar}]3{\mathrm{d}}^5$ :

1. A.$\mathrm{Ru}$
2. B.$\mathrm{Mn}$
3. C.$\mathrm{Co}$
4. D.$\mathrm{Fe}$

A $50\mathrm{watt}$ bulb emits monochromatic red light of wavelength of $795\mathrm{nm}$. The number of photons emitted per second by the bulb is $x\times 10^{20}$. The value of x is ____. [Given : $h=6.63\times 10^{-34}\mathrm{Js}$ and $c=3.0\times 10^8\mathrm{m}{\mathrm{s}}^{-1}$]

A metal surface is exposed to 500 nm radiation. The threshold frequency of the metal for photoelectric current is $4.3\times 10^{14}\text{ Hz}$. The velocity of ejected electron is ___________ $\times 10^5{\text{ ms}}^{-1}$ (Nearest integer) [$\text{Use : }h=6.63\times 10^{-34}\text{ Js}$, $m_e=9.0\times 10^{-31}\text{ kg}$]

Given below are two statements : Statement I : Hyperconjugation is a permanent effect. Statement II : Hyperconjugation in ethyl cation $\left(C{H}_3-\stackrel{+}{C}{H}_2\right)$ involves the overlapping of $C_{s{p}^2}-H_{1s}$ bond with empty 2p orbital of other carbon. Choose the correct option :

1. A.Both statement I and statement II are false
2. B.Statement I is incorrect but statement II is true
3. C.Statement I is correct but statement II is false
4. D.Both statement I and statement II are true.

Match List - I with List - II : | | List - I | | List - II | |---|---|---|---| | (a) | Li | (i) | photoelectric cell | | (b) | Na | (ii) | absorbent of $C{O}_2$ | | (c) | K | (iii) | coolant in fast breeder nuclear reactor | | (d) | Cs | (iv) | treatment of cancer | | | | (v) | bearings for motor engines | Choose the correct answer from the options given below :

1. A.(a) - (v), (b) - (i), (c) - (ii), (d) - (iv)
2. B.(a) - (v), (b) - (ii), (c) - (iv), (d) - (i)
3. C.(a) - (iv), (b) - (iii), (c) - (i), (d) - (ii)
4. D.(a) - (v), (b) - (iii), (c) - (ii), (d) - (i)

The total number of electrons in all bonding molecular orbitals of $O_2^{2-}$ is __________. (Round off to the nearest integer)

An accelerated electron has a speed of $5\times 10^6\mathrm{m}{\mathrm{s}}^{-1}$ with an uncertainty of 0.02%. The uncertainty in finding its location while in motion is $x\times 10^{-9}$ m. The value of x is ____. (Nearest integer) [Use mass of electron = $9.1\times 10^{-31}$ kg, h = $6.63\times 10^{-34}$ Js, $\pi$ = 3.14]

Number of electrons present in 4f orbital of $\mathrm{H}{\mathrm{o}}^{3+}$ ion is ____. (Given Atomic No. of Ho = 67)

Match List-I with List-II : $$\begin{array}{llll}& \text{List-I}& & \text{List-II}\\ & \text{(Species)}& & \text{(Hybrid Orbitals)}\\ \text{(a)}& \mathrm{S}{\mathrm{F}}_4& \text{(i)}& \mathrm{s}{\mathrm{p}}^3{\mathrm{d}}^2\\ \text{(b)}& \mathrm{I}{\mathrm{F}}_5& \text{(ii)}& {\mathrm{d}}^2\mathrm{s}{\mathrm{p}}^3\\ \text{(c)}& \mathrm{N}{\mathrm{O}}_2^{+}& \text{(iii)}& \mathrm{s}{\mathrm{p}}^3\mathrm{d}\\ \text{(d)}& \mathrm{N}{\mathrm{H}}_4^{+}& \text{(iv)}& \mathrm{s}{\mathrm{p}}^3\\ & & \text{(v)}& \mathrm{sp}\end{array}$$ Choose the correct answer from the options given below :

1. A.(a)-(i), (b)-(ii), (c)-(v) and (d)-(iii)
2. B.(a)-(ii), (b)-(i), (c)-(iv) and (d)-(v)
3. C.(a)-(iii), (b)-(i), (c)-(v) and (d)-(iv)
4. D.(a)-(iv), (b)-(iii), (c)-(ii) and (d)-(v)

Match List-I with List-II $$\begin{array}{llll}& \text{List-I (Elements)}& & \text{List-II (Properties)}\\ \text{(a)}& \text{Ba}& \text{(i)}& \text{Organic solvent soluble compounds}\\ \text{(b)}& \text{Ca}& \text{(ii)}& \text{Outer electronic configuration }6s^2\\ \text{(c)}& \text{Li}& \text{(iii)}& \text{Oxalate insoluble in water}\\ \text{(d)}& \text{Na}& \text{(iv)}& \text{Formation of very strong monoacidic base}\end{array}$$ Choose the correct answer from the options given below :

1. A.(a)-(ii), (b)-(iii), (c)-(i) and (d)-(iv)
2. B.(a)-(iv), (b)-(i), (c)-(ii) and (d)-(iii)
3. C.(a)-(iii), (b)-(ii), (c)-(iv) and (d)-(i)
4. D.(a)-(i), (b)-(iv), (c)-(ii) and (d)-(iii)

Number of electrons that Vanadium (Z = 23) has in p-orbitals is equal to _____________

The Azimuthal quantum number for the valence electrons of ${\text{Ga}}^{+}$ ion is ________. (Atomic number of $\text{Ga}=31$)