Chapter 4

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) \(\mathrm{E}_{1}=6 \mathrm{E}_{2}\) (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) \(\mathrm{Z}>\mathrm{Y}>\mathrm{X}\) (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) \(4 \lambda\)

The correct order of number of unpaired electrons in the ion \(\mathrm{Cu}^{2+} \mathrm{Ni}^{2+}, \mathrm{Fe}^{3+}\) and \(\mathrm{Cr}^{3+}\) is (a) \(\mathrm{Cu}^{2+}>\mathrm{Ni}^{2+}>\mathrm{Cr}^{3+}>\mathrm{Fe}^{3+}\) (b) \(\mathrm{Ni}^{2+}>\mathrm{Cu}^{2+}>\mathrm{Fe}^{3+}>\mathrm{Cr}^{3+}\) (c) \(\mathrm{Fe}^{3+}>\mathrm{Cr}^{3+}>\mathrm{Ni}^{2+}>\mathrm{Cu}^{2+}\) (d) \(\mathrm{Fe}^{3+}>\mathrm{Cr}^{3+}>\mathrm{Cu}^{2+}>\mathrm{Ni}^{2+}\)

The energy ratio of a photon of wavelength \(3000 \AA\) and \(6000 \AA\) is (a) \(1: 1\) (b) \(2: 1\) (c) \(1: 2\) (d) \(1: 4\)

The energy ratio of a photon of wavelength \(3000 \AA\) and \(6000 \AA\) is (a) \(1: 1\) (b) \(2: 1\) (c) \(1: 2\) (d) \(1: 4\)

The de Broglie wavelength associated with a particle of mass \(10^{-6} \mathrm{~kg}\) moving with a velocity of \(10 \mathrm{~ms}^{-1}\) is (a) \(6.63 \times 10^{-7} \mathrm{~m}\) (b) \(6.63 \times 10^{-16} \mathrm{~m}\) (c) \(6.63 \times 10^{-21} \mathrm{~m}\) (d) \(6.63 \times 10^{-29} \mathrm{~m}\)

In hydrogen atom, energy of first excited state is \(-3.4\) \(\mathrm{eV}\). The kinetic energy of the same orbit of hydrogen atom would be (a) \(+3.4 \mathrm{eV}\) (b) \(+6.8 \mathrm{eV}\) (c) \(-13.6 \mathrm{eV}\) (d) \(+13.6 \mathrm{eV}\)

The velocity of an electron in the second shell of hydrogen atom is (a) \(10.94 \times 10^{6} \mathrm{~ms}^{-1}\) (b) \(18.88 \times 10^{6} \mathrm{~ms}^{-1}\) (c) \(1.888 \times 10^{6} \mathrm{~ms}^{-1}\) (d) \(1.094 \times 10^{6} \mathrm{~ms}^{-1}\)

Electron energy of a photon is given as: \(\Delta \mathrm{E} /\) atom \(=3.03 \times 10^{-19} \mathrm{~J}\) atom \(^{-1}\) then, the wavelength of the photon is (a) \(6.56 \mathrm{~nm}\) (b) \(65.6 \mathrm{~nm}\) (c) \(656 \mathrm{~nm}\) (d) \(0.656 \mathrm{~nm}\) Given, h (Planck constant) \(=6.63 \times 10^{-34} \mathrm{Js} \mathrm{c}\) (velocity of light \()=3.00 \times 10^{8} \mathrm{~ms}^{-1}\)

If the nitrogen atom has electronic configuration \(1 \mathrm{~s}^{7}\), it would have energy lower than that of the normal ground state configuration \(1 \mathrm{~s}^{2} 2 \mathrm{~s}^{2} 2 \mathrm{p}^{3}\), because the electrons would be closer to the nucleus. Yet \(1 \mathrm{~s}^{7}\) is not observed because it violates (a) Heisenberg uncertainty principle (b) Hund's rule (c) Pauli's exclusion principle (d) Bohr postulates of stationary orbits

Radial nodes present in \(3 \mathrm{~s}\) and \(2 \mathrm{p}\) orbitals are respectively (a) 0,2 (b) 2,0 (c) 2,1 (d) 1,2

The radius of which of the following orbits is same as that of the first Bohr's orbit of hydrogen atom? (a) \(\mathrm{He}^{+}(\mathrm{n}=2)\) (b) \(\mathrm{Li}^{2+}(\mathrm{n}=2)\) (c) \(\mathrm{Li}^{2+}(\mathrm{n}=3)\) (d) \(\mathrm{Be}^{3+}(\mathrm{n}=2)\)

The wavelength associated with a golf ball weighing \(200 \mathrm{~g}\) and moving at a speed of \(5 \mathrm{~m} / \mathrm{h}\) is of the order (a) \(10^{-10} \mathrm{~m}\) (b) \(10^{-20} \mathrm{~m}\) (c) \(10^{-30} \mathrm{~m}\) (d) \(10^{-40} \mathrm{~m}\)

Which of the following statement(s) are correct? (1) the electronic configuration of \(\mathrm{Cr}\) is \([\mathrm{Ar}] 3 \mathrm{~d}^{5} 4 \mathrm{~s}^{1}\) (atomic number of \(\mathrm{Cr}=24\) ) (2) the magnetic quantum number may have a negative value (3) in silver atom, 23 electrons have a spin of one type and 24 of the opposite type (atomic number of \(\mathrm{Ag}=47\) )

For a d-electron, the orbital angular momentum is (a) \(\sqrt{6} \mathrm{~h}\) (b) \(\sqrt{2 h}\) (c) \(\mathrm{h}\) (d) \(2 \mathrm{~h}\)

The orbital angular momentum of an electron in \(2 \mathrm{~s}\) orbital is (a) \(+\frac{1}{2} \cdot \frac{h}{2 \pi}\) (b) zero (c) \(\frac{h}{2 \pi}\) (d) \(\sqrt{2} \frac{h}{2 \pi}\)

The mass of an electron is \(\mathrm{m}\). Its charge is e and it is accelerated from rest through a potential difference \(\mathrm{V}\). The velocity acquired by the electron will be (a) \(\sqrt{\mathrm{V} / \mathrm{m}}\) (b) \(\mathrm{VeV} / \mathrm{m}\) (c) \(\sqrt{2 \mathrm{e}} \mathrm{V} / \mathrm{m}\) (d) none

The mass of an electron is \(\mathrm{m}\). Its charge is e and it is accelerated from rest through a potential difference \(\mathrm{V}\). The velocity acquired by the electron will be (a) \(\sqrt{\mathrm{V} / \mathrm{m}}\) (b) \(\mathrm{VeV} / \mathrm{m}\) (c) \(\sqrt{2 \mathrm{e}} \mathrm{V} / \mathrm{m}\) (d) none

A \(600 \mathrm{~W}\) mercury lamp emits monochromatic radiation of wavelength \(331.3 \mathrm{~nm}\). How many photons are emitted from the lamp per second? \(\left(\mathrm{h}=6.626 \times 10^{-34} \mathrm{~J} \mathrm{~s} ;\right.\) velocity of light \(=3 \times 10^{8} \mathrm{~ms}^{-1}\) (a) \(1 \times 10^{19}\) (b) \(1 \times 10^{20}\) (c) \(1 \times 10^{21}\) (d) \(1 \times 10^{23}\)

The shortest wavelength in hydrogen spectrum of Lyman series when \(\mathrm{R}_{H}=109678 \mathrm{~cm}^{-1}\) is (a) \(1002.7 \AA\) (b) \(1215.67 \AA\) (c) \(1127.30 \AA\) (d) \(911.7 \AA\)

Correct set of four quantum numbers for the valence (outermost) electron of rubidium \((Z=37)\) is (a) \(5,0,0, \pm 1 / 2\) (b) \(6,0,0,+1 / 2\) (c) \(5,1,1, \pm 1 / 2\) (d) \(5,1,0, \pm 1 / 2\)

The increasing order (lowest first) for the values of \(\mathrm{e} / \mathrm{m}\) (charge/mass) for electron (e), proton (p), neutron (n) and alpha particle (a) is (a) \(\mathrm{n}, \mathrm{p}, \mathrm{a}, \mathrm{e}\) (b) \(\mathrm{n}, \mathrm{p}, \mathrm{e}, \mathrm{a}\) (c) \(\mathrm{n}, \mathrm{a}, \mathrm{p}, \mathrm{e}\) (d) e, p, n, a

The ionization energy of hydrogen atom is \(13.6 \mathrm{eV}\). What will be the ionization energy of \(\mathrm{He}^{+}\)? (a) \(13.6 \mathrm{eV}\) (b) \(54.4 \mathrm{eV}\) (c) \(122.4 \mathrm{eV}\) (d) zero

If \(\mathrm{S}\), be the specific charge \((\mathrm{e} / \mathrm{m})\) of cathode rays and \(\mathrm{S}_{2}\) be that of positive rays then which is true? (a) \(\mathrm{S}_{1}=\mathrm{S}_{2}\) (b) \(\mathrm{S}_{1}<\mathrm{S}_{2}\) (c) \(\mathrm{S}_{1}>\mathrm{S}_{2}\) (d) None of these

Predict the total spin in \(\mathrm{Ni}^{2+}\) ion (a) \(\pm 5 / 2\) (b) \(\pm 3 / 2\) (c) \(\pm 1 / 2\) (d) \(\pm 1\)

The orbital diagram in which Aufbau principle is violated is (a) \(\uparrow \downarrow \quad \uparrow \downarrow \uparrow\) (b) \(\uparrow\) (c) \(\uparrow \downarrow \quad \uparrow|\uparrow| \uparrow \mid\) (d) \(\uparrow \downarrow\)

For the electronic transition from \(\mathrm{n}=2 \rightarrow \mathrm{n}=1\) which of the following will produce shortest wave length? (a) \(\mathrm{Li}^{2+}\) ion (b) D atom (c) He' ion (d) \(\mathrm{H}\) atom

For \(\mathrm{n}=2\) the correct set of \(\ell, \mathrm{m}\) are (a) \(\ell=2, \mathrm{~m}=-2,-1,0+1,+2\) (b) \(\ell=1 \mathrm{~m}=-2,-1,0+1,+2\) (c) \(\ell=1 \mathrm{~m}=-1,0,+1\) (d) \(\ell=0 \mathrm{~m}=-1,0,+1\)

The charge cloud of a single electron in a \(2 \mathrm{p}_{\mathrm{x}}\) atomic orbital has two lobes of electron density. This means (a) there is a high probability of locating the electron in a \(2 \mathrm{p}_{x}\) atomic orbital at values of \(\mathrm{x}>0\) (b) there is a great probability of finding a p electron right at the nucleus (c) there is a high probability of locating it values of \(x<0\) but no probability at alloy locating if any where in the yz plane along which \(\mathrm{x}=0\). (d) both (a) and (c)

The wavelength of the de Broglie wave of the electron revolving in the fifth orbit of the hydrogen atom is \(\left(\mathrm{r}_{0}\right.\) is the Bohr's radius \(=0.529 \AA\) ) (a) \(20 \mathrm{r}_{0}\) (b) \((10 \pi) \mathrm{r}_{0}\) (c) \(5 \pi \mathrm{r}_{0}\) (d) \(15 \pi \mathrm{r}_{0}\)

The de Broglie wavelength associated with a ball of mass \(1 \mathrm{~kg}\) having a kinetic energy \(0.5 \mathrm{~J}\) is (a) \(6.626 \times 10^{-34} \mathrm{~m}\) (b) \(13.2 \times 10^{-34} \mathrm{~m}\) (c) \(10.38 \times 10^{-21} \mathrm{~m}\) (d) \(6.626 \AA\)

The size of a microscopic particle is one micron and its mass is \(6 \times 10^{-13} \mathrm{gm}\). If its position may be measured to within \(0.1 \%\) of its size, the uncertainty in velocity, in \(\mathrm{cm} \mathrm{s}^{-1}\), is approximately (a) \(10^{-6} / 3 \pi\) (b) \(10^{-7} / 2 \pi\) (c) \(10^{-5} / 4 \pi\) (d) \(10^{-7} / 4 \pi\)

The size of a microscopic particle is one micron and its mass is \(6 \times 10^{-13} \mathrm{gm}\). If its position may be measured to within \(0.1 \%\) of its size, the uncertainty in velocity, in \(\mathrm{cm} \mathrm{s}^{-1}\), is approximately (a) \(10^{-6} / 3 \pi\) (b) \(10^{-7} / 2 \pi\) (c) \(10^{-5} / 4 \pi\) (d) \(10^{-7} / 4 \pi\)

What is the wavelength of the radiation emitted produced in a line in the Lyman series when an electron falls from fourth stationary state in hydrogen atom? \(\left(\mathrm{R}_{\mathrm{H}}=1.1 \times 10^{7} \mathrm{~m}^{-1}\right)\) (a) \(96.97 \mathrm{~nm}\) (b) \(969.7 \mathrm{~nm}\) (c) \(9.697 \mathrm{~nm}\) (d) none

Rearrange the following (I to IV) in the order of in creasing masses and choose the correct answer from (a), (b), (c), (d). (atomic masses: \(\mathrm{N}=14, \mathrm{O}=\) \(16, \mathrm{Cu}=63)\) I. 1 molecule of oxygen II. 1 atom of nitrogen III. \(1 \times 10^{10} \mathrm{~g}\) molecular weight of oxygen IV. \(1 \times 10^{-18} \mathrm{~g}\) atomic weight of copper (a) II \(<\mathrm{I}<\mathrm{IV}<\mathrm{III}\) (b) IV < III < II