CBSE Questions for Class 11 Medical Chemistry Structure Of Atom Quiz 13 - MCQExams.com

A substance can be identified because its chemical environment often shows up like a finger print in a spectrum. This fine region of finger prints of the chemical environment of a chemical compound is created by:
  • infrared radiation
  • ultraviolet light
  • nuclear magnetic resonance
  • $$X-$$rays
An ionic atom equivalent to hydrogen atom has wavelength equal to $$\dfrac{1}{4}$$ of the wavelengths of hydrogen lines. The ion will be
  • $$He^+$$
  • $$Li^{++}$$
  • $$Ne^{9+}$$
  • $$Na^{10+}$$
Ionization potential of hydrogen is $$13.6$$ volt. If it is excited by a photon of energy $$12.1eV$$, then the number of lines in the emission spectrum will be:
  • $$2$$
  • $$3$$
  • $$4$$
  • $$5$$
The gyromagnetic ratio of an electron in an $$H-$$atom, according to Bohr model, is:-
  • Independent of which orbit it is in
  • Negative
  • Positive
  • Increase with the quantum number $$n$$
The frequency of the characterstic X ray of $$K_a$$ line of metal targent 'M' is $$2500 cm^{-1}$$ and the graph between $$\sqrt { v } $$ Vs 'z' is as follows, then atomic number of M is?

1078698_072af105e8cf422280a82882f5353120.png
  • $$49$$
  • $$50$$
  • $$51$$
  • $$25$$
Angular momentum in second Bohr orbit of H-atom is $$x$$. Then find out angular momentum in 1st excited state of $${Li}^{+2}$$ ion:
  • $$3x$$
  • $$9x$$
  • $$\cfrac{x}{2}$$
  • $$x$$
The emission spectra of atoms in the gaseous phase do not show a continuous spread of wavelength from red to violet, rather they emit light only at specific wavelengths with dark spaces between them. Such spectra is/are called:
  • line spectra
  • atomic spectra
  • both $$(A)$$ and $$(B)$$
  • none of these
If one were to apply Bohr's model to a particle of mass 'm' and charge 'q' moving in a plane under the influence of a magnetic field 'B', the energy of the charged particles in the $$n^{th}$$ level will be:
  • n$$(\dfrac{hqB}{8\pi m})$$
  • n$$(\dfrac{hqB}{4\pi m})$$
  • n$$(\dfrac{hqB}{2\pi m})$$
  • n$$(\dfrac{hqB}{\pi m})$$
Assuming Bohr's model for $$ Li^{++} $$ atom, the first excitatio energy of ground state of $$ Li^{++} $$ atom is
  • 10.2 eV
  • 91.8 eV
  • 13.6 eV
  • 3.4 eV
The third line of Balmer series of an ion equivalent to hydrogen atom has wavelength of $$108.5nm$$. the ground state energy of an electron of this ion will be
  • $$3.4eV$$
  • $$13.6eV$$
  • $$54.4eV$$
  • $$122.4eV$$
The wavelength of the first member of the Balmer series in hydrogen spectrum is $$x$$ $$\mathring{A}$$. Then the wavelength (in $$\mathring{A}$$) of the first member of Lyman series in the same spectrum is
  • $$\cfrac{5}{27}x$$
  • $$\cfrac{4}{3}x$$
  • $$\cfrac{27}{5}x$$
  • $$\cfrac{5}{36}x$$
In a hypothetical system a particle of mass $$m$$ and charge $$-3q$$ is moving around a very heavy particle having charge $$q$$. Assuming Bohr's model to be true to this system, the orbital velocity of mass $$m$$ when it is nearest to the heavy particle is
  • $$\cfrac{3{q}^{2}}{2{\epsilon}_{0}h}$$
  • $$\cfrac{3{q}^{2}}{4{\epsilon}_{0}h}$$
  • $$\cfrac{3{q}^{}}{2{\epsilon}_{0}h}$$
  • $$\cfrac{3{q}^{}}{4{\epsilon}_{0}h}$$
The mass of two moles of nitrogen atom is_____
  • $$28\space g$$
  • $$14\space g$$
  • $$7\space g$$
  • $$20\space g$$
If the boiling point of ethanol (molecular weight = 46 ) is $$78^o$$C, the boiling point of diethyl ether (molecular weight = 74) is 
  • $$100^o$$C
  • $$78^o$$C
  • $$86^o$$C
  • $$34^o$$C
Find an expression for de Broglie wavelength for an electron in the $$n^{th}$$ orbit of the Bohr model of the hydrogen atom and hence find its value when the electron is in n = 4 level.
Take radius of nth orbital of Bohr's model of H-atom; $$r_n = (53 \ n^2) $$ pm
  • 1.33 nm
  • 1.20 nm
  • 1.50 nm
  • None
Which principle/ rule limits the maximum number of electrons in orbital to two?
  • Aufbau principle
  • Pauli's exclusion principle
  • Hund's rule of maximum multiplicity
  • Heisenberg's uncertainty principle
Which of the following are isotopes?
(i) Atom, whose nucleus contains 20p+15n
(ii) Atom whose nucleus contains 20p+17n
(iii) Atom, whose nucleus contains 18p+22n
(iv) Atom, whose nucleus contains 18p+21n
  • (i) and (iii)
  • (i) and (ii)
  • (ii) and (iii)
  • (ii) and (iv)
Which of the following elements is non- radioactive?
  • plutonium
  • Zirconium
  • Thorium
  • Uranium
Calculate minimum number of electrons in $$Fe$$ atom having $$(n+l) \ge 4,\ m=-1, \ s=+\frac { 1 }{ 2 } $$.
  • 1
  • 2
  • 3
  • 4
An electron jumps from the $$4^{th}$$ orbit to the $$2^{nd}$$ orbit of hydrogen atom $$(R=10^{5}\ Cm^{-1})$$. Frequency is in $$Hz$$ of emitted radiation will be
  • $$\dfrac {3\ \times 10^{5}}{16}$$
  • $$\dfrac {3\ \times 10^{15}}{16}$$
  • $$\dfrac {9\ \times 10^{15}}{16}$$
  • $$\dfrac {9\ \times 10^{5}}{16}$$
Which of the following radiations has largest energy ?
  • $$\lambda = 30$$ nm
  • $$\lambda = 300$$ pm
  • $$v = 3\times 10^{12}$$ s$$^{-1}$$
  • $$v = 3\times 10^{10}$$ s$$^{-1}$$
According to Bohr's theory of the hydrogen atom, the speed $$v_n$$ of the electron in a stationary orbit is related to the principal quantum number n as (C is a constant).
  • $$v_n=C/n^2$$
  • $$v_n=C/n$$
  • $$v_n=C\times n$$
  • $$v_n=C\times n^2$$
The average life of an excited state of hydrogen atom is of the order $${ 10 }^{ -8 }s$$. The number of revolution made by an electron when it is in state n= 2 and before it suffers a transition to state n = 1 are
  • $${ 8.23\times 10 }^{ 6 }$$
  • $${ 2.82\times 10 }^{ 6 }$$
  • $${ 22.8\times 10 }^{ 6 }$$
  • $${ 2.28\times 10 }^{ 6 }$$
Atomic number of $$N$$ is $$7$$. The atomic number of 3rd member of nitrogen family is 
  • 23
  • 15
  • 33
  • 43
In a hypothetical system a particle of mass m and charge -3 q is moving around a very heavy particle having charge q. Assuming Bohr's model to be true to this system, the orbital velocity of mass m when it is nearest to heavy particle is:
  • $$\frac{3q^2}{2\varepsilon _0h}$$
  • $$\frac{3q^2}{4\varepsilon _0h}$$
  • $$\frac{3q}{2\varepsilon _0h}$$
  • $$\frac{3q}{4\varepsilon _0h}$$
$${ M }^{ 3+ }$$ has electronic configuration as $$[Ar]{ 3d }^{ 10 }{ 4s }^{ 2 }$$. Hence it lies in:
  • s-block
  • p- block
  • d-block
  • f-block
Which of the following is inversely proportional to the square of principal quantum number in Bohr's atomic model?
  • Total energy of the electron in $$n^{th}$$ orbit.
  • Radius of the $$n^{th}$$ orbit.
  • Frequency of revolution in $$n^{th}$$ orbit.
  • Time period of revolution in $$n^{th}$$ orbit.
In an atom having $$2K, 8L, 8M$$ and $$2N$$ electrons, the number of electrons with $$m=0$$; $$s=+\dfrac{1}{2}$$ are?
  • $$6$$
  • $$2$$
  • $$8$$
  • $$16$$
Suppose that in any Bohr atom (or) ion orbits are only in even numbers like $$2,4,6,....$$ the maximum wavelength of radiation emitted in the visible region of hydrogen spectrum should be ______________.
  • $$\dfrac{4}{R}$$
  • $$\dfrac{R}{4}$$
  • $$\dfrac{36}{5R}$$
  • $$\dfrac{16}{3R}$$
In a hydrogen like sample electron is in $$2nd$$ excited state, the binding energy of $$4th$$ state of this sample is $$-13.6\ eV$$, then incorrect statement is :
  • Atomic number of element is $$4$$.
  • $$3$$ different types of spectral line will be observed if electrons make transition upto ground state from the $$2nd$$ excited state.
  • A $$25\ eV$$ photon can set free the electron from the $$2nd$$ excited state of this sample.
  • $$2nd$$ line of Balmer series of this sample has same energy value as $$1st$$ excitation energy of $$H-$$atoms.
What is the maximum number of electrons that can be accommodated in the outermost orbit?
  • 2
  • 8
  • 3
  • 18
The speed of sound in air is $$v$$. Both the source and observer are moving towards each other with equal speed $$u$$. The speed of wind is$$w$$ from source to observer. Then, the ratio $$(\cfrac{f}{{f}_{0}})$$ of the apparent frequency to the actual frequency is given by
  • $$\cfrac{v+u}{v-u}$$
  • $$\cfrac{v+w+u}{v+w-u}$$
  • $$\cfrac{v+w+u}{v-w-u}$$
  • $$\cfrac{v-w+u}{v-w-u}$$
Which of the following orbitals has the lowest energy?
  • $$4d$$
  • $$4f$$
  • $$5s$$
  • $$5p$$
According to Moseley's law, the ratio of the slope of graph between $$\sqrt { f } $$ and $$Z$$ for $${ k }_{ \beta  }$$ and $${ k }_{ \alpha  }$$ is
  • $$\sqrt { \dfrac { 32 }{ 27 } } $$
  • $$\sqrt { \dfrac { 27 }{ 32 } } $$
  • $$\sqrt { \dfrac { 5 }{ 56 } } $$
  • $$\sqrt { \dfrac { 36 }{ 5 } } $$
The ratio of masses of an element A attached with the fixed mass of another element B in their two compounds is 2:If 48 mass of A is attached with 24 mass of B in first compound then what mass of A is attached with the 12 mass of b in the second compound?
  • 72
  • 36
  • 24
  • 12
The electric potential between a proton and an electron is given by $$V=VIn\dfrac { r }{ { r }_{ 0 } } $$, where $${ r }_{ 0 }$$ is a constant. Assuming Bohr's model to be applicable,write variation of $${ r }_{ n}$$ with $$n,\ n$$ being the principal quantum number.
  • $${ r }_{ n }\propto n$$
  • $${ r }_{ n }\propto \dfrac { 1 }{ n } $$
  • $${ r }_{ n }\propto { n }^{ 2 }$$
  • $${ r }_{ n }\propto \dfrac { 1 }{ { n }^{ 2 } } $$
For an atom with atomic number 14, the number of orbits and orbitals in which electrons are present is respectively:
  • $$3,6$$
  • $$6,3$$
  • $$7,3$$
  • $$3,8$$
One Bohr magneton is equal to ____________ $${ AM }^{ 2 }$$.
  • $$4.8\times { 10 }^{ -10 }eSu$$
  • $$1.6\times { 10 }^{ -19 }eSu$$
  • $$4.8\times { 10 }^{ -10 }\ eSu\ \& 1.6\times { 1 0}^{ -19 } \ eSu$$
  • $$9.27\times { 10 }^{ -24 }$$
The de Broglie wavelength of an electron in $$n^{th}$$ Bohr orbit of radius $$a_n(a_0$$ being the first orbit radius$$)$$:
  • $$2\pi a_0$$
  • $$2\pi n^2a_0$$
  • $$2\pi na_0$$
  • $$\dfrac{2\pi a_0}{n}$$
The ground state energy of hydrogen atom is $$-13.6$$ eV. The energy of second excited state $$He^+ ion$$ in eV is:
  • $$-6.04$$
  • $$-27.2$$
  • $$-54.4$$
  • $$-3.4$$
After the filling of np-orbitals next orbital filled will be:
  • ns
  • nd
  • (n-1)d
  • (n+1)s
The number of the spectral lines obtained when an electron is provided with a photon of the energy of $$11\  eV$$ (for H atom) is/are:
  • $$1$$
  • $$2$$
  • $$0$$
  • $$6$$
Imagine an atom made of a proton and a hypothetical particle of double the mass as that of an electron but the same charge. Apply Bohr theory to consider transitions of the hypothetical particle to the ground state . Then, the longest wavelength (in terms of Rydberge constant for hydrogen atom ) is
  • $$\dfrac { 1 } { 2 R }$$
  • $$\dfrac { 5} { 3 R }$$
  • $$\dfrac { 1 } { 3 R }$$
  • $$\dfrac { 2 } { 3 R }$$
Which is correct statement about proton?
  • Proton is nucleus of deuterium.
  • Proton is ionized oxygen molecule.
  • Proton is ionized hydrogen atom.
  • None of these
FUNDAMENTAL PARTICLES 
Nucleus  was discovered in 
  • discharge of electricity through gases
  • the bormbarding experiment Wilson
  • $$\alpha $$-ray scattering experiment
  • Wilson cloud chamber
The time taken by the electron in one complete revolution in the $$n^{th}$$ Bohr's orbit of the hydrogen atom is 
  • Inversely proportional to $$n^2$$
  • Directly proportional to $$n^3$$
  • Directly proportional to $$\dfrac{h}{2\pi}$$
  • Inversely proportional to $$\dfrac{n}{h}$$
Which of the following elements has two shells, both of which are completely filled with electrons? 
  • Hydrogen (H)
  • Boron (B)
  • Helium (He)
  • Neon (Ne)
The hydrogen atom in ground state is excited by a monochromatic radiation of $$  \lambda=975 A^{\circ}  $$ . Number of spectral lines in the resulting spectrum emitted will be
  • 3
  • 2
  • 6
  • 10
Consider the following given species and find out, for which Bohr's atomic model is not applicable?
  • $$
    1^{H^{2}}
    $$
  • $$He^{ + }$$
  • $$
    H^{+}
    $$
  • $$
    \mathrm{Li}^{2+}
    $$
Which of the following gas is mono-atomic?
  • Chlorine
  • Helium
  • Hydrogen
  • Oxygen
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