CBSE Questions for Class 11 Medical Chemistry Structure Of Atom Quiz 9 - MCQExams.com

The electronic configuration of an element is $$1s^2, 2s^2, 2p^6, 3s^23p^3$$. What is the atomic number of the element which is just below the given element in the periodic table?
  • $$34$$
  • $$49$$
  • $$33$$
  • $$31$$
$$12\ g$$ of a trivalent element combines with $$4\ g$$ of oxygen. Its atomic mass is:
  • $$48$$
  • $$72$$
  • $$3$$
  • $$36$$
The orbit having Bohr radius equal to $$1^{st}$$ Bohr orbit of $$H-$$atom is:
  • $$n=2$$ of $$He^{+}$$
  • $$n=2$$ of $$B^{+4}$$
  • $$n=3$$ of $$Li^{+2}$$
  • $$n=2$$ of $$Be^{+3}$$
The number of orbitals in n = 3 are:
  • 1
  • 4
  • 9
  • 16
The active mass of $$7.0\ g$$ of nitrogen in a $$2.0\ L$$ container would be:
  • $$0.25$$
  • $$0.125$$
  • $$0.5$$
  • $$14.0$$

The key feature Of Bohr's theory Of spectrum Of hydrogen atom is the quantization Of angular momentum when an electron is revolving around a proton. We will extend this to a general rotational motion to find quantized rotational energy Of a diatomic molecule assuming it to be rigid. The rule to be applied is Bohr's quantization condition.A diatomic molecule has moment Of inertia I. By Bohr's quantization condition its rotational energy in the nth level (n=0 is not allowed) is 
  • $$\cfrac{h^2}{(n^2)(8\pi^2I)}$$
  • $$\cfrac{h^2}{(n)(8\pi^2I)}$$
  • $$\cfrac{n h^2}{8\pi^2I}$$
  • $$\cfrac{n^2 h^2}{(8\pi^2I)}$$
$$7.8$$ grams of metal in water and liberated $$2.24L$$ of hydrogen at standard conditions. Calculate the atomic number of the metal.
  • $$23$$
  • $$24$$
  • $$7$$
  • $$19$$
  • $$35$$

Which of the following statement is not correct?
1093820_92bbbfae819642f4bfe2dddecfe51ecb.png
  • Atomic no.of A,B,C are $$40,57,105$$ respectively
  • Group no of A, B,C are IV B, III B and V B respectively
  • Period no of A, B,C are 4th , 5th and 6th respectively
  • C is a radioactive element
Moseley's equation is represented as $$\sqrt { v } =a(Z-b)$$ where a and b are constants If $$OA=1$$, then atomic number of the elements showing frequency of $$400Hz$$ is?
1096661_4ff8b5b5558e454a88f9675292bfedb4.PNG
  • 21
  • 11
  • 401
  • 19
Visible spectrum lies between:
  • 400nm to 760 nm
  • 350nm to 760 nm
  • 400nm to 660 nm
  • 300nm to 760 nm
What is the potential energy of an electron present in N-shell of the $${ B }e^{ 3+ } ion$$?
  • $$-3.4 eV$$
  • $$-6.8 eV$$
  • $$-13.6 eV$$
  • $$-27.2 eV$$
The orbit from which when electron will jump in other orbit, energy may be absorbed but not emitted out, will be?
  • $$1$$st orbit
  • $$2$$nd orbit
  • $$7$$th orbit
  • infinite orbit
The second is the duration of $$9 192 631 770$$ periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium $$133$$ atom.
  • True
  • False
What atomic number of an element $$X$$ would have to become so that the $$4th$$ orbit around $$X$$ would fit inside the $$1st$$ Bohr orbit of $$H-$$atom?
  • 3
  • 4
  • 16
  • 25
What is the seperation energy (in eV) for $$Be^{3+}$$ in the first excited state in eV?
  • $$13.6eV$$
  • $$27.2eV$$
  • $$40.8eV$$
  • $$54.4eV$$
Suppose that A and B form the compounds $$B_2A_3$$ and $$B_2A$$. If 0.05 mole of $$B_2A_3$$ weighs 9 g and 0.1 mole of $$B_2A$$ weighs 10 g, the atomic weight of A and B respectively are:
  • 30 and 40
  • 40 and 30
  • 20 and 5
  • 15 and 20
The mass of an element $$E$$ found in $$1.00\ mole$$ of each of four different compounds is $$38.0\ g$$, $$57.0\ g$$, $$76.0\ g$$ and $$114\ g$$ respectively . 

What is possible atomic weight of $$E$$?
  • $$19.0$$
  • $$38$$
  • $$57$$
  • $$76$$
Energy of the third orbit of Bohr's atom is:
  • $$-13.6$$ eV
  • $$-3.4$$ eV
  • $$-1.5$$ eV
  • none of these
Which element with lowest atomic number .
  • $$_{19}K$$
  • $$_{24}Cr$$
  • $$_{11}Na$$
  • $$_{29}Cu$$
What is the ratio of time periods $$(\dfrac{T_1}{T_2})$$ in $$2^{nd}$$ orbit of hydrogen atom to third orbit of $$He^+$$ ion?
  • $$\dfrac{8}{27}$$
  • $$\dfrac{32}{27}$$
  • $$\dfrac{27}{32}$$
  • $$\dfrac{27}{8}$$
If the ratio of the radius of the two different nuclei is 2:3; then what will be the ratio of their mass? 
(If density is same)
  • 16:27
  • 4:81
  • 8:27
  • 5:25
A single electron orbits a stationary nucleus of charge $$+Z$$, where $$Z$$ is a constant. It requires 47.2 eV to excite electron from second Bohr orbit to third Bohr orbit, find the value of $$Z$$.
  • 1
  • 3
  • 5
  • 4
Multiple of fine structure of spectral lines is due to:
  • presence of main energy levels
  • presence of sub-level
  • presence of electronic configuration
  • is not a characteristics of the atom.
If the speed of electrons in Bohr's first obtain of hydrogen is $$'X'$$ the speed of electrons in third orbit is:
  • $$\dfrac {X}{9}$$
  • $$\dfrac {X}{3}$$
  • $$3X$$
  • $$9X$$
For Hydrogen atom the ratio of time required to complete $$1$$ revolution of electron in $$I^{st},II^{nd}$$ and $$III^{rd}$$ orbit respectively is:
  • $$1:8:27$$
  • $$1:4:9$$
  • $$1:2:3$$
  • $$1:16:81$$
What happens to the atomic number during a chemical reaction?
  • It increases.
  • It changes.
  • Remains the same.
  • Changes alternatively.
Which of the following parameters are not same for all hydrogen like atoms and ions in their state?
  • Radius of orbit
  • Speed of electron
  • Energy of the atom
  • Orbital angular momentum of electron
Which of the following frequencies is associated with the visible region of a spectrum?
  • $$3\times10^9$$ cycle /seconds
  • $$6\times10^{14}$$ cm cycle /seconds
  • $$5.0\times10^{10-3}$$ cycle /seconds
  • None of these
The ratio of the radius of $$1st$$ orbit of $$H$$ atom to that of its $$4$$th excited state is:
  • $$\dfrac{1}{5}$$
  • $$\dfrac{1}{25}$$
  • $$25$$
  • $$\dfrac{1}{16}$$
According to Bohr's atomic theory, which of the following is correct?
  • Potential energy of electrom $$\alpha $$$$\dfrac{Z^2}{n^2}$$
  • The product of velocity of electron and principle quantum number (n) $$\alpha Z^2$$
  • Frequency of revolution of electron in an orbit $$\alpha \dfrac{Z^2}{n^3}$$
  • Coulombic force of attraction on the electron $$\alpha \dfrac{Z^2}{n^2}$$
A trend common to both group $$I$$ and $$VII$$ elements in the periodic table as atomic number increase is 
  • Atomic radius increase
  • Oxidising power increase
  • Reactivity with water increase
  • Maximum valency increase
Potassium selenate is isomorphous with the potassium sulphate and contains 50.0% of $$Se$$. Find the atomic weight of $$Se$$.
  • 142
  • 71
  • 47.33
  • 284
Atomic number of the central atom in $${ MCl }_{ 2 }$$ is $$50$$. The shape of gaseous $${ MCl }_{ 2 }$$ is given as: 
The moment of momentum of electrons in the third orbit in a hydrogen atom 
  • $$31.67 \times 10^{-34} gm \ m^2/s$$
  • $$3.167 \times 10^{-34} kg \ m^2/s$$
  • $$31.67 \times 10^{-34} kg \ cm^2/s$$
  • $$31.67 \times 10^{-34} gm \ cm^2/s$$
Ionization energy of $${He}^{+}$$ is $$19.6\times {10}^{-18}J{atom}^{-1}$$. The energy of the first stationary state ($$n=1$$) of $${Li}^{2+}$$ is
  • $$4.41\times {10}^{-16}J{atom}^{-1}$$
  • $$-4.41\times {10}^{-17}J{atom}^{-1}$$
  • $$-2.2\times {10}^{-15}J{atom}^{-1}$$
  • $$-8.82\times {10}^{-17}J{atom}^{-1}$$
Approximate atomic weight is of an element is $$26.89 \; g$$. If its equivalent weight is $$8.9 \; g$$, the exact atomic weight of element would be:
  • $$29.89$$
  • $$8.9$$
  • $$17.8$$
  • $$26.7$$
Name the compounds used in preparation of nylon-66.
  • E-caprolactum
  • Hexamethylenediamine and adipic acid
  • Dimethyl tetraphthalate
  • Hexamethylene diamine
The radius of first excited state of $${ Be }^{ 3+ }$$ ion is:
  • $$0.53\overset { o }{ A } $$
  • $$\cfrac { 0.53 }{ 4 } \overset { o }{ A } $$
  • $$0.53\times 4\overset { o }{ A } $$
  • $$0.53\times 2\overset { o }{ A } $$
The e/m of proton is
  • $$1.78\times {10}^{8}C/g$$
  • $$9.57\times {10}^{4}C/g$$
  • $$19.14\times {10}^{4}C/g$$
  • $$0.478\times {10}^{4}C/g$$
Which of the following hydrogen bonds are strongest in vapour phase?
  • $$HF.....HF$$
  • $$HF...HCl$$
  • $$HCl...HCl$$
  • $$HF...HI$$
The unfavorable electrochemical reaction among the following is:
The radius of the hydrogen atom in the ground state is $$0.53 {\mathring A}$$, the radius of $$L{i^{2 + }}$$ in a similar state is____.
  • $$1.06 {\mathring A}$$
  • $$0.265 {\mathring A}$$
  • $$0.175 {\mathring A}$$
  • $$0.53 {\mathring A}$$
Which among the following elements does not contain same number of s-electrons as the number of d-electrons in $${ Ni }^{ 2+ }$$? (Atomic number of Kr is 36) 
  • Ca
  • Kr
  • Cu
  • Fe
Which of the atomic number represents s -block elements?
  • 7, 15
  • 3, 12
  • 6, 12
  • 9, 17
The radius of the first Bohr orbit of a hydrogen atom is $$ 0.53\times 10^{-10}m$$.When an electron collides with this atom which is in its normal state, the radius of the electron orbit in the atom change to $$2.12 \times 10^{10}m$$.The value of the principal quantum number $$n$$ of the state to which it is excited is:
  • $$4$$
  • $$3$$
  • $$2$$
  • $$1$$
If transition of an electron in $$H-atom$$ takes place from $$3rd$$ orbit to $$5th$$ then change in angular momentum of electron is given by?
  • $$h$$
  • $$\dfrac{h}{2}$$
  • $$2h$$
  • $$3h$$
Bohr's theory can be applied to determine the?
  • electron gain enthalpy of hydrogen atom
  • Electronegativity of $${ Li }^{ 2+ }$$ ion
  • second ionization energy of helium atom
  • first ionization energy of Be atom
The ratio between the number of neutrons present in $$C^{12}$$ and $$Si^{30}$$ atoms is:
  • 3:8
  • 2:5
  • 3:7
  • 1:1
The ratio of the energy of the electron in the ground state of hydrogen to the electron in first excited state of $$Be^{3+}$$ is 
  • $$1 : 4$$
  • $$1 : 8$$
  • $$1 : 16$$
  • $$16 : 1$$
In a hydrogen atom the force acting on the electron is proportional to :
  • $$n^{4}$$
  • $$n^{-4}$$
  • $$r^{2}$$
  • $$n^{-2}$$
0:0:1


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