Chapter 4

How many e \(^{-}\)are present in p-sub-orbits in \(\mathrm{Zn}\)-atom? (a) 2 (b) 6 (c) 12 (d) 18

Wavelength of spectral line emitted is inversely proportional to (a) energy (b) velocity (c) radius (d) quantum number

The number of electrons, neutrons and protons in a species are equal to 10,8 and 8 respectively. The proper symbol of the species is (a) \({ }^{16} \mathrm{O}_{8}\) (b) \({ }^{18} \mathrm{O}_{8}\) (c) \({ }^{18} \mathrm{Ne}_{10}\) (d) \({ }^{16} \mathrm{O}_{8}^{6}=\)

Which one of the following forms a colourless solution in aqueous medium? (a) \(\mathrm{V}^{3+}\) (b) \(\mathrm{Cr}^{3+}\) (c) \(\mathrm{Ti}^{3+}\) (d) \(\mathrm{Sc}^{3+}\) Atomic number \(\mathrm{Sc}=21, \mathrm{Ti}=22, \mathrm{~V}=23, \mathrm{Cr}=24\)

The incorrect configuration is (a) \(\mathrm{K}=[\mathrm{Ar}] 4 \mathrm{~s}^{1}\) (b) \(\mathrm{Cr}=[\mathrm{Ar}] 3 \mathrm{~d}^{5} 4 \mathrm{~s}^{1}\) (c) \(\mathrm{Cr}=[\mathrm{Ar}] 3 \mathrm{~d}^{4} 4 \mathrm{~s}^{2}\) (d) \(\mathrm{Cu}=[\mathrm{Ar}] 3 \mathrm{~d}^{10} 4 \mathrm{~s}^{1}\)

Which of the following elements has least number of electrons in its M shell? (a) \(\mathrm{Mn}\) (b) \(\mathrm{Ni}\) (c) \(\mathrm{K}\) (d) \(\mathrm{Sc}\)

In which orbital is the angular momentum of an electron zero? (a) \(2 \mathrm{p}\) (b) \(2 \mathrm{~s}\) (c) \(3 \mathrm{~d}\) (d) \(4 \mathrm{f}\)

Chromium is represented by the electronic configuration (a) \([\mathrm{Ne}] 3 \mathrm{~s}^{2} 3 \mathrm{p}^{6} 3 \mathrm{~d}^{1} 4 \mathrm{~s}^{2}\) (b) \([\mathrm{Ne}] 3 \mathrm{~s}^{2} 3 p^{6} 3 \mathrm{~d}^{2} 4 \mathrm{~s}^{1}\) (c) \([\mathrm{Ne}] 3 \mathrm{~s}^{2} 3 \mathrm{p}^{6} 3 \mathrm{~d}^{5} 4 \mathrm{~s}^{1}\) (d) \([\mathrm{Ne}] 3 \mathrm{~s}^{2} 3 \mathrm{p}^{6} 4 \mathrm{~s}^{2} 3 \mathrm{~d}^{4}\)

The correct set of quantum numbers is (a) \(\mathrm{n}=2, l=1, \mathrm{~m}=-2, \mathrm{~s}=0\) (b) \(\mathrm{n}=2, l=-2, \mathrm{~m}=1, \mathrm{~s}=+1 / 2\) (c) \(\mathrm{n}=2, l=2, \mathrm{~m}=-1, \mathrm{~s}=-1 / 2\) (d) \(\mathrm{n}=2, l=1, \mathrm{~m}=0, \mathrm{~s}=+1 / 2\)

The values of four quantum numbers of valence electron of an element are \(\mathrm{n}=4, l=0, \mathrm{~m}=0\) and \(\mathrm{s}=+1 / 2\) The element is (a) Ti (b) \(\mathrm{K}\) (c) \(\mathrm{Na}\) (d) \(\mathrm{Sc}\)

Set of isoelectronic species is (a) \(\mathrm{H}_{2}, \mathrm{CO}_{2}, \mathrm{CN}^{-}, \mathrm{O}^{-}\) (b) \(\mathrm{N}, \mathrm{H}_{2} \mathrm{~S}, \mathrm{CO}\) (c) \(\mathrm{N}_{2}, \mathrm{CO}, \mathrm{CN}^{-}, \mathrm{O}_{2}^{+2}\) (d) \(\mathrm{Ca}, \mathrm{Mg}, \mathrm{Cl}\)

Number of orbitals in \(L\) energy level (a) 1 (b) 2 (c) 3 (d) 4

Ratio of radii of second and first Bohr orbits of \(\mathrm{H}\) atom is (a) 2 (b) 4 (c) 3 (d) 4

If a source of power \(4 \mathrm{Kw}\) produces \(10^{20}\) photon Per second, the radiation belongs to a part of the spectrum called (a) \(\gamma\)-Rays (b) U.V Rays (c) Microwaves (d) X-Rays

The outer most configuration of most electronegative element is (a) \(\mathrm{ns}^{2} \mathrm{np}^{5}\) (b) \(\mathrm{ns}^{2} \mathrm{np}^{6}\) (c) \(\mathrm{ns}^{2} \mathrm{np}^{4}\) (d) \(\mathrm{ns}^{2} \mathrm{np}^{6}\)

Quantum numbers of an atom can be defined on the basis of (a) Aufbau's principle (b) Heisenberg's uncertainity principle (c) Hund's rule (d) Pauli's exclusion principle

Which of the following is isoelectronic? (a) \(\mathrm{CO}_{2}, \mathrm{NO}_{2}\) (b) \(\mathrm{NO}_{2}^{-}, \mathrm{CO}_{2}\) (c) \(\mathrm{CN}^{-}, \mathrm{CO}\) (d) \(\mathrm{SO}_{2}, \mathrm{CO}_{2}\)

Which of the following do not travel with speed of light? (a) De-Broglie waves (b) X-rays (c) Gamma rays (d) All of these

How many electrons can be accommodated in a p-orbital? (a) 6 electrons (b) 2 electrons (c) 4 electrons (d) none of these

The quantum number 'm' of a free gaseous atom is associated with (a) the effective volume of the orbital (b) the shape of the orbital (c) the spatial orientation of the orbital (d) the energy of the orbital in the absence of a magnetic field

The number of nodal planes in a px orbital is (a) 1 (b) 2 (c) 3 (d) 0

How many d-electrons are present in \(\mathrm{Cr}^{2+}\) ion? (a) 5 (b) 6 (c) 3 (d) 4

\(l=3\), then the values of magnetic quantum numbers are \(\AA\) (a) \(\pm 1, \pm 2, \pm 3\) (b) \(0, \pm 1, \pm 2, \pm 3\) (c) \(-1,-2,-3\) (d) \(0,+1,+2,+3\)

Which one of the following pairs of ions have the same electronic configuration? (a) \(\mathrm{Sr}^{3+}, \mathrm{Cr}^{3+}\) (b) \(\mathrm{Fe}^{3+}, \mathrm{Mn}^{2+}\) (c) \(\mathrm{Fe}^{3+}, \mathrm{Co}^{3+}\) (d) \(\mathrm{Cr}^{3+}, \mathrm{Fe}^{3+}\)

The atomic number of an element is 35 . What is the total number of electrons present in all the p-orbitals of the ground state atom of that element? (a) 17 (b) \(\mathrm{ll}\) (c) 23 (d) 6

The atomic number of an element is 17 . The number of orbitals electron pairs in its valence shell is (a) 3 (b) 4 (c) 6 (d) 8

The correct representation for d orbital is (a) \((\mathrm{n}-1) \mathrm{d}^{1-9} \mathrm{~ns}^{1}\) (b) \((\mathrm{n}-1) \mathrm{d}^{1-10} \mathrm{~ns}^{1-2}\) (c) \((\mathrm{n}-1) \mathrm{d}^{1-5}\) (d) \((\mathrm{n}-\mathrm{l}) \mathrm{d}^{1-10} \mathrm{~ns}^{2}\)

An element has 2 electrons in its \(\mathrm{K}\) shell, 8 electrons in L shell, 13 electrons in \(\mathrm{M}\) shell and one electron in \(\mathrm{N}\) shell. The element is (a) \(\mathrm{Cr}\) (b) \(\mathrm{Fe}\) (c) \(\mathrm{V}\) (d) Ti

Effective magnetic moment of \(\mathrm{Sc}^{3+}\) ion is (a) 0 (b) \(1.73\) (c) \(2.83\) (d) \(3.87\)

Which of the following is not possible? (a) \(\mathrm{n}=2, l=1, \mathrm{~m}=0\) (b) \(\mathrm{n}=2, l=0, \mathrm{~m}=-1\) (c) \(\mathrm{n}=3, l=0, \mathrm{~m}=0\) (d) \(\mathrm{n}=3, l=1, \mathrm{~m}=-1\)

The most probable radius (in \(\mathrm{pm}\) ) for finding the electron in \(\mathrm{He}^{+}\)is (a) \(105.8\) (b) \(52.9\) (c) \(26.5\) (d) \(0.0\)

In which of the following pairs are both the ions coloured in aqueous solution? (a) \(\mathrm{Sc}^{3+}, \mathrm{Co}^{2+}\) (b) \(\mathrm{Ni}^{2+}, \mathrm{Cu}^{+}\) (c) \(\mathrm{Ni}^{2+}, \mathrm{Ti}^{3+}\) (d) \(\mathrm{Sc}^{3+}, \mathrm{Ti}^{3+}\) (At. no. \(\mathrm{Sc}=21, \mathrm{~T}_{1}=22, \mathrm{Ni}=28, \mathrm{Cu}=29, \mathrm{Co}=27\) )

When potassium metal is exposed to violet light (a) there is no effect (b) ejection of electron takes place (c) the absorption of electrons takes place (d) ejection of some potassium atoms occurs

Rutherford's experiment, which established the nuclear model of the atom, used a beam of (a) \(\beta\)-particles, which impinged on a metal foil and got absorbed (b) \(\gamma\)-rays, which impinged on a metal foil and ejected electrons (c) Helium atoms, which impinged on a metal foil and got scattered (d) Helium nuclei, which impinged on a metal foil and got scatterd.

The quantum number \(+1 / 2\) and \(-1 / 2\) for the electron spin represent (a) rotation of the electron in clockwise and anticlockwise direction respectively. (b) rotation of the electron in anti clockwise and clockwise direction respectively. (c) magnetic moment of the electron pointing up and down respectively. (d) two quantum mechanical spin states which have no classical analogues.

The angular momentum (L) of an electron in a Bohr orbit is given as (a) \(\mathrm{L}=\mathrm{nh} / 2 \pi\) (b) \(V[l(l+1) \mathrm{h} / 2 \pi\) (c) \(\mathrm{L}=\mathrm{mg} / 2 \pi\) (d) \(\mathrm{L}=\mathrm{h} / 4 \pi\)

Which one of the following is the standard for atomic mass? (a) \({ }_{1} \mathrm{H}^{1}\) (b) \(\mathrm{C}^{12}\) (c) \({ }_{6} \mathrm{C}^{4}\) (d) \({ }_{8} \mathrm{O}^{16}\)

Which of the following relates to photons both as wave motion and as a stream of particles? (a) interference (b) \(\mathrm{E}=\mathrm{mc}^{2}\) (c) diffraction (d) \(\mathrm{E}=\mathrm{h} v\)

Electromagnetic radiation with maximum wavelength is (a) radiowave (b) X-ray (c) infraredt (d) ultraviolet

When the \(\mathrm{e}^{-}\)of a \(\mathrm{H}\)-atom moves from \(\mathrm{n}=4\) to \(\mathrm{n}=1\) the number of spectral lines emitted is (a) 3 (b) 6 (c) 9 (d) 15

Which set represents the quantum Numbers of 19 th electron in Cr-atom? (a) \(4,0,0,1 / 2\) (b) \(4,1,0,1 / 2\) (c) \(3,2,2,1 / 2\) (d) \(3,2,-2,1 / 2\)

The fourth electron of Be atom will have which of the following quantum numbers? (a) \(1,0,0,1 / 2\) (b) \(2,0,0,-1 / 2\) (c) \(2,1,0,+1 / 2\) (d) \(1,1,1,+1 / 2\)

The Angular momentum of an \(\mathrm{e}\) - can't be (a) \(\frac{\mathrm{h}}{\pi}\) (b) \(\frac{2 \mathrm{~h}}{2 \pi}\) (c) \(\frac{2.5 h}{2 \pi}\) (d) \(\frac{0.5 h}{\pi}\)

If the wavelength of an electromagnetic radiation is \(2000 \AA\). What is the energy in ergs? (a) \(9.92 \times 10^{-19}\) (b) \(9.94 \times 10^{-12}\) (c) \(4.97 \times 10^{-12}\) (d) \(4.97 \times 10^{-19}\)

The value of Planck constant is \(6.63 \times 10^{-34} \mathrm{Js}\). he velocity of light is \(3.0 \times 10^{8} \mathrm{~m} \mathrm{~s}^{-1} .\) which value is closest to the wavelength in nanometres of a quantum of light with frequency of \(8 \times 10^{15} \mathrm{~s}^{-1}\) ? (a) \(4 \times 10^{1}\) (b) \(3 \times 10^{7}\) (c) \(2 \times 10^{-2 s}\) (d) \(5 \times 10^{-18}\)

The frequency of radiation emitted when the electron falls from \(\mathrm{n}=4\) to \(\mathrm{n}=1\) in a hydrogen atom will be (Given ionization energy of \(\mathrm{H}=2.18 \times 10^{18} \mathrm{~J}\) atom \(^{-1}\) and \(\mathrm{h}=6.625 \times 10^{-34} \mathrm{Js}\) ) (a) \(1.54 \times 10^{15} \mathrm{~s}^{-1}\) (b) \(1.03 \times 10^{15} \mathrm{~s}^{-1}\) (c) \(3.08 \times 10^{15} \mathrm{~s}^{-1}\) (d) \(2.00 \times 10^{15} \mathrm{~s}^{-1}\)

Among the following series of transition metal ions, the one where all metal ion have \(3 \mathrm{~d}^{2}\) electronic configuration is (a) \(\mathrm{Ti}^{3+}, \mathrm{V}^{2+}, \mathrm{Cr}^{3+}, \mathrm{Mn}^{4+}\) (b) \(\mathrm{Ti}^{+}, \mathrm{V}^{4+}, \mathrm{Cr}^{6+}, \mathrm{Mn}^{7+}\) (c) \(\mathrm{Ti}^{\prime 4}, \mathrm{~V}^{3+}, \mathrm{Cr}^{2+}, \mathrm{Mn}^{3+}\) (d) \(\mathrm{Ti}^{2+}, \mathrm{V}^{3+}, \mathrm{Cr}^{4+}, \mathrm{Mn}^{5+}\) (At. wt \(\mathrm{Ti}=22, \mathrm{~V}=23, \mathrm{Cr}=24 \mathrm{Mn}=25)\)

The relationship between energy \(\mathrm{E}\), of the radiation with a wavelength \(8000 \AA\) and the energy of the ra diation with a wavelength \(16000 \AA\) is (a) \(\mathrm{E}_{1}=2 \mathrm{E}_{2}\) (b) \(\mathrm{E}_{1}=4 \mathrm{E}_{2}\) (c) \(E_{1}=6 E_{2}\) (d) \(\mathrm{E}_{1}=\mathrm{E}_{2}\)

The atomic numbers of elements \(\mathrm{X}, \mathrm{Y}, \mathrm{Z}\) are \(19.21\) and 25 respectively. The number of electrons present in the 'M' shells of these elements follow the order (a) \(Z>Y>X\) (b) \(\mathrm{X}>\mathrm{Y}>\mathrm{Z}\) (c) \(\mathrm{Z}>\mathrm{X}>\mathrm{Y}\) (d) \(\mathrm{Y}>\mathrm{Z}>\mathrm{X}\)

An electron is moving in Bohr's fourth orbit, its de-Broglie wavelength is \(X\). What is the circumference of the fourth orbit? (a) \(2 \lambda\) (b) \(2 / \lambda\) (c) \(3 \lambda\) (d) \(4 \lambda\)