CBSE Questions for Class 11 Medical Chemistry Structure Of Atom Quiz 12 - MCQExams.com

To explain his theory, Bohr-used
  • Conservation of linear momentum
  • Conservation of angular momentum
  • Conservation of quantum frequency
  • Conservation of energy
In Bohr's model of hydrogen atom, which of the following pairs of quantities are quantized
  • Energy and linear momentum
  • Linear and angular momentum
  • Energy and angular momentum
  • None of these
The main particle of the outer part of an atom is
  • Proton
  • Neutron
  • Proton and Neutron
  • Electron
Which of the following is quantised according to Bohr's theory of hydrogen atom 
  • Linear momentum of electron
  • Angular momentum of electron
  • Linear velocity of electron
  • Angular velocity of electron
The total number of atoms per unit cell in bcc is:
  • 3
  • 1
  • 4
  • 2
The boher model of atoms
  • Assume that the angular momentum of electrons is quantized
  • Uses Einstein's photo electric equation
  • Predicts continuous emission spectra for atoms
  • Predicts the same emission spectra for all types of atoms
In hydrogen atom which quantity is integral multiple of $$\dfrac{h}{2\pi}$$
  • Angular momentum
  • Angular velocity
  • Angular acceleration
  • Momentum
When a hydrogen atom is raised from ground to excited state.
  • The P.E increases and K.E decreases
  • The P.E decreases and K.E increases
  • Both P.E and K.E increase
  • Both P.E and K.E decreases
If $$n = 3 , l = 0 , m = 0 $$ then atomic number is 
  • $$12 , 13 $$
  • $$13 , 14 $$
  • $$10 , 11 $$
  • $$11 , 12 $$
In the ground state, an element has $$13$$ electrons in its M-shell. The element is
  • Manganese
  • Chromium
  • Nickel
  • Iron
The maximum number of electrons in an orbit with $$l = 2 , n = 3 $$ is 
  • $$2$$
  • $$6$$
  • $$12$$
  • $$10$$
Any p-orbital can accommodate upto
  • four electrons
  • two electrons with parallel spin
  • six electrons
  • two electrons with anti-parallel spin.
Naturally occurring B consists of two isotopes, whose atomic weights are 10.01 and 11.The atomic weight of natural boron is 10.The % of each isotope in natural boron is :
  • % of isotope of mass 10.01 = 20, % of isotope of mass 11.01 = 80
  • % of isotope of mass 10.01 = 30, % of isotope of mass 11.01 = 70
  • % of isotope of mass 10.01 = 50, % of isotope of mass 11.01 = 50
  • none of these
In what ratio Cl$$_{17}^{37}$$ and Cl$$_{17}^{35}$$ be present so as to obtain Cl$$_{17}^{35.5}$$?
  • 1 : 2
  • 1 : 1
  • 1 : 3
  • 3 : 1
According to Bohr's theory of hydrogen-atom, for the electron in the $$n^{th}$$ permissible orbit
  • $$\mbox{Linear Momentum } \propto \displaystyle\frac{1}{n}$$
  • $$\mbox{Radius of orbit } \propto n$$
  • $$\mbox{Kinetic Energy } \propto \displaystyle\frac{1}{n^2}$$
  • $$\mbox{Angular Momentum } \propto n$$
How are isotopes of the same element different?
  • They will have different locations on the periodic table.
  • They will have different numbers of electrons.
  • They will have undergo different chemical reactions.
  • They have different numbers of protons.
  • They have different numbers of neutrons.
If Aufbau rule is not obeyed and the electronic filling occurs orbit by orbit till saturation is reached (for a given principal quantum number $$n$$, electrons are filled in the increasing order of azimuthal quantum number $$l$$), then the percentage change in sum of all $$(n + l)$$ values for unpaired electrons in an atom of iron is $$10x$$. What is the value of $$x$$?
  • $$5$$
  • $$6$$
  • $$7$$
  • $$3$$
What principle is violated here?
  • Laws of Motion
  • Energy conservation
  • Nothing is violated
  • Cannot be decided
In Bohr's model of an atom :
  • Electrons revolve around the nucleus in circular orbits.
  • These circular orbits or shells are stationary.
  • Each shell in associated with a definite amount of energy.
  • All shells have equal energy level.
Maximum number of electrons in a subshell of an atom is determined by the following:
  • $$\text{2l+2}$$
  • $$\text{4l-1}$$
  • $$2n^2$$
  • $$\text {4l + 2}$$
Many elements have fractional atomic mass. This is because of :
  • they have isotopes
  • their isotopes have non-integral masses
  • their isotopes have different masses
  • neutrons, protons and electrons combine to give fractional masses
For the hydrogen atom, the energy of the electron is defined by the factor $$E_n=-13.58/n^2 eV$$. Here n is positive integer. The minimum quantity of energy which it can absorb in its primitive stage is:
  • $$1.00 eV$$
  • $$3.39 eV$$
  • $$6.79 eV$$
  • $$10.19 eV$$
The total number of electrons that could be held in a sub-level with azimuthal quantum number = 2 is :
  • $$2$$
  • $$6$$
  • $$8$$
  • $$10$$
The maximum number of electrons in a shell with the principal quantum number =  4 is :
  • $$2$$
  • $$10$$
  • $$16$$
  • $$32$$
If the principle quantum number n = 6, the correct sequence of filling of electron will be : 
  • $$ns\rightarrow$$ $$(n - 2)f$$ $$\rightarrow$$ np $$\rightarrow (n - 1)$$
  • $$ns\rightarrow$$ $$(n - 1)f$$ $$\rightarrow$$ $$np$$ $$\rightarrow (n - 2)$$
  • $$ns\rightarrow np\rightarrow(n - 1)d\rightarrow(n - 2)f$$
  • $$ns\rightarrow (n - 2)f \rightarrow (n - 1)d \rightarrow np$$
Statement I : $$\displaystyle ^{ 12 }{ C }\ $$ is an isotope of  $$\displaystyle ^{ 14 }{ C }\ $$.
Statement II: The nuclei of both atoms have the same number of neutrons.
  • true, false
  • false, true
  • false, false
  • true, true, correct explanation
If the principal quantum number of a shell is 2, what types of orbitals will be present?
  • $$s$$
  • $$s$$ and $$ p$$
  • $$s,\ p$$ and $$d$$
  • $$s,\ p,\ d$$ and $$f$$
Designations of some orbitals are given below. Arrange the orbitals with possible designations in the order in which they are filled with electrons $$6s,\ 8p,\ 7s,\ 4d,\ 2p,\ 3d,\ 3f,\ 4f$$.
  • $$2p < 3d < 4d < 4p < 6s < 8p < 7s<4f$$
  • $$2p < 3d < 4p < 4d < 6s < 4f < 7s < 8p$$
  • $$3d < 2p < 4p < 4d < 6s < 4f < 7s < 8p$$
  • $$2p < 3d < 4p < 4d < 4f < 6s < 7s < 8p$$
Which letter orbital corresponds to $$l$$ = 2?
  • S
  • p
  • d
  • f
  • n
Which color of light has the highest energy?
  • Violet
  • Green
  • Yellow
  • Orange
  • Red
An element $$X$$ combines with oxygen to form compounds $$P$$ and $$Q$$. If the ratio of the valency of element $$X$$ in $$P$$ to element $$X$$ in $$Q$$ is $$3 : 5$$ respectively, what could be the probable compounds $$P$$ and $$Q$$?
  • $$\begin{matrix} P & Q \\ CO & C{ O }_{ 2 } \end{matrix}$$
  • $$\begin{matrix} P & Q \\ { N }_{ 2 }{ O }_{ 3 } & { N }_{ 2 }{ O }_{ 5 } \end{matrix}$$
  • $$\begin{matrix} P & Q \\ { H }_{ 2 }O & { H }_{ 2 }{ O }_{ 2 } \end{matrix}$$
  • $$\begin{matrix} P & Q \\ C{ H }_{ 4 } & { C }_{ 3 }{ H }_{ 6 } \end{matrix}$$
The ratio of the energy of photon of $$2000 A^0$$ wavelength to that of $$4000 A^0$$ wavelength is:
  • 1 : 4
  • 4 : 1
  • 1 : 2
  • 2 : 1
Two trials of a reaction were run in a lab where absorbance data was collected over time.
In trial $$2$$, the absorbance values for the reaction for each unit of time were higher than they were for trial $$1$$.
Also, the rate of trial $$2$$ was higher than that of trial $$1$$.
Which of the following is most likely the case?
  • The concentration of one or more reactants was increased in trial $$2$$.
  • The concentration of the reactants in trial $$1$$ was higher than that in trial $$2$$.
  • The concentration of reactants was decreased for trial $$2$$.
  • Something interfered with the reaction.
Which of the following statements is TRUE of matter?
  • The states of matter are interconvertible
  • Force of attraction varies from one kind of matter to another
  • The states of matter can be changed by changing the temperature of pressure
  • All of the above
Beer's Law states that $$A = abc$$, where A is absorbance, a is the molar absorptivity constant, b is the path length, and c is the molar concentration.
Which of the following would be an incorrect application of Beer's Law?
  • The path length is irrelevant, as long as it is inversely proportional to the molar concentration when determining the concentration of an unknown as compared to a standard curve.
  • The molar concentration is directly related to absorption of light by the sample and is used to develop a standard curve.
  • The concentration of an unknown sample can be easily determined from a standard curve of known concentrations plotted against absorbance for a fixed path length.
  • The use of Beer's Law and a spectrophotometer for a colored sample is a better method of determining molar concentration than visual comparison.
Gas A is a colorless gas and Gas B is orange in color. Consider the absorbance data for gases A and B when they were analyzed through spectroscopy.
Which of the following statements best explains the data?
528584.jpg
  • More energy is required to make Gas A molecules vibrate than Gas B.
  • The ionization energy of Gas B atom is higher than Gas A.
  • Gas A has more electrons compared to Gas B.
  • There are lower energy transitions available in Gas B compared to Gas A.
A man writes his biodata with carbon pencil on the plane paper having mass 150 mg. After writing his biodata, he weighs the written paper and find its mass 152 mg. What is the number of carbon atoms present in the paper?
  • $$1.0036 \times 10^{20}$$
  • $$5.02 \times 10^{20}$$
  • $$1.0036 \times 10^{23}$$
  • $$0.502 \times 10^{20}$$
The predominant yellow line in the spectrum of a sodium vapour lamp has a wavelength of $$590 nm$$. What minimum accelerated potential is needed to excite this line in an electron tube having sodium vapours?
  • $$8.44$$ volt.
  • $$2.11$$ volt.
  • $$6.11$$ volt.
  • $$4.22$$ volt.
Which of the following orbitals has the highest energy?
  • $$5d$$
  • $$5f$$
  • $$6s$$
  • $$6p$$
In ground state of chromium atom $$(Z=24)$$ the total number of orbitals populated by one or more electrons is?
  • $$15$$
  • $$16$$
  • $$20$$
  • $$14$$
The highest energy in Balmer series, in the emission spectra of hydrogen is represented by:
$$\left({R}_{H}=109737 {cm}^{-1}\right)$$
  • $$4389.48 {cm}^{-1}$$
  • $$2194.74 {cm}^{-1}$$
  • $$5486.85 {cm}^{-1}$$
  • $$27434.25 {cm}^{-1}$$
The number of revolutions per second made by an electron in the first Bohr's orbit of hydrogen atom is(Given, $$r=0.53\overset{o}{A}$$).
  • $$6\times 10^5$$Hz
  • $$2.5\times 10^{12}$$Hz
  • $$1.9\times 10^{13}$$Hz
  • $$6.5\times 10^{15}$$Hz
The mass of photon having wavelength $$1 nm$$ is:
  • $$2.21\times { 10 }^{ -35 }kg$$
  • $$2.21\times { 10 }^{ -33 }g$$
  • $$2.21\times { 10 }^{ -33 }kg$$
  • $$2.21\times { 10 }^{ -26 }kg$$
The fast emission line on hydrogen atomic spectrum in the Balmer series appears at:

[$$R =$$ Rydberg constant]
  • $$\dfrac{5R}{36}cm^{-1}$$
  • $$\dfrac{3R}{4}cm^{-1}$$
  • $$\dfrac{7R}{144}cm^{-1}$$
  • $$\dfrac{9R}{400}cm^{-1}$$
The magnitude of potential energy of an electron in the second Bohr orbit of a hydrogen atom is:
[$$a_0$$ is Bohr radius].
  • $$\dfrac{h^2}{4 \pi^2 ma_o^2}$$
  • $$\dfrac{h^2}{16 \pi^2 ma_o^2}$$
  • $$\dfrac{h^2}{32 \pi^2 ma_o^2}$$
  • $$\dfrac{h^2}{64 \pi^2 ma_o^2}$$
The figure shown the wavelength spectrum of x-rays produced when $$50 \ KeV$$ electrons strike a molybdenum target. The $${ K }_{ \alpha  }$$ line on the figure is represent by a number:
995919_6965167b59c84648b78840d568cbe52e.PNG
  • $$1$$
  • $$2$$
  • $$3$$
  • none
Calculate the wavelength of the first line of $$He^{+}$$ ion spectral series whose interval with extreme lines is:
$$\dfrac{1}{\lambda_{1}} - \dfrac{1}{\lambda_{2}} = 2.7541 \times 10^{4} cm^{-1}$$
  • $$4869 \overset{o}{A}$$
  • $$1651 \overset{o}{A}$$
  • $$3039 \overset{o}{A}$$
  • $$2175 \overset{o}{A}$$
Bohr's theory can also be applied to the ions like :
  • $$He^+$$
  • $$Li^{2+}$$
  • $$Be^{3+}$$
  • All of the these
Time taken for an electron to complete one in revolution in Bohr orbit of hydrogen atom is :
  • $$\frac{4\pi^2 mr^2}{nh}$$
  • $$\frac{nh}{4\pi^2 mr}$$
  • $$\frac{2\pi mr}{n^2h^2}$$
  • $$\frac{h}{2\pi mr}$$
If the radial probability curve indicates $$2s$$ orbital, the distance between the peak points X and Y is?
770812_e8b3482acb6940fd9ccf90f3838e3406.png
  • $$2.07\overset{o}{A}$$
  • $$1.59\overset{o}{A}$$
  • $$0.53\overset{o}{A}$$
  • $$2.12\overset{o}{A}$$
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