CBSE Class 11 Chemistry Structure Of Atom Worksheet Set B

Structure Of Atom MCQ Questions with Answers Class 11 Chemistry

Question- The shortest wavelength in hydrogen spectrum of Lyman series when RH = 109678 cm^–1 is

(a) 1002.7Å

(b) 1215.67Å

(c) 1127.30Å

(d) 911.7Å

Answer-(d)

Question-The radius of hydrogen atom in the ground state is 0.53 Å.The radius of Li²⁺ ion (atomic number = 3) in a similar state is

(a) 0.17 Å

(b) 0.265 Å

(c) 0.53 Å

(d) 1.06 Å

Answer-(a)

Question-The energy of an electron in second Bohr orbit of hydrogen atom is :

(a) –5.44 × 10^–19eV

(b) –5.44 × 10^–19cal

(c) –5.44 × 10^–19kJ

(d) –5.44 × 10^–19J

Answer-(d)

Question-What does negative sign in the electronic energy for hydrogen atom convey.

(a) Energy of electron when n = ∞

(b) The energy of electron in the atom is lower than the energy of a free electron in motion

(c) The energy of electron in the atom is lower than the energy of a free electron of rest

(d) The energy of electron decreases as it moves away from nucleus

Answer-(c)

Question- Which of the following statements do not form a part of Bohr’s model of hydrogen atom ?

(a) Energy of the electrons in the orbits are quantized

(b) The electron in the orbit nearest the nucleus has the lowest energy

(c) Electrons revolve in different orbits around the nucleus

(d) The position and velocity of the electrons in the orbit cannot be determined simultaneously.

Answer-(d)

Question-The wavelength of the radiation emitted, when in a hydrogen atom electron falls from infinity to stationary state 1, would be (Rydberg constant = 1.097×10⁷ m^–1)

(a) 406 nm

(b) 192 nm

(c) 91 nm

(d) 9.1×10^–8 nm

Answer-(c)

Question-If the energy difference between the ground state of an atom and its excited state is 4.4 × 10^–4 J, the wavelength of photon required to produce the transition :

(a) 2.26 × 10^–12 m

(b) 1.13 × 10^–12 m

(c) 4.52 × 10^–16 m

(d) 4.52 × 10^–12 m

Answer-(d)

Question-According to the Bohr theory, which of the following transitions in the hydrogen atom will give rise to the least energetic photon ?

(a) n = 6 to n = 1

(b) n = 5 to n = 4

(c) n = 6 to n = 5

(d) n = 5 to n = 3

Answer-(c)

Question-The mass of a photon with a wavelength equal to 1.54 × 10^–8 cm is

(a) 0.8268 × 10^–34 kg

(b) 1.2876 × 10^–33 kg

(c) 1.4285 × 10^–32 kg

(d) 1.8884 × 10^–32 kg

Answer-(c)

Question-Bohr model can explain :

(a) the solar spectrum

(b) the spectrum of hydrogen molecule

(c) spectrum of any atom or ion containing one electron only

(d) the spectrum of hydrogen atom only

Answer-(c)

Question-In a hydrogen atom, if energy of an electron in ground state is 13.6. eV, then that in the 2nd excited state is

(a) 1.51 eV

(b) 3.4 eV

(c) 6.04 eV

(d) 13.6 eV.

Answer-(a)

Question-The line spectrum of He⁺ ion will resemble that of

(a) hydrogen atom

(b) Li⁺ ion

(c) helium atom

(d) lithium atom

Answer-(a)

Question-Bohr’s theory can be applied to which of the following ions.

(a) Na⁺

(b) Be²⁺

(c) Li⁺

(d) Li²⁺

Answer-(d)

Question-If r is the radius of the first orbit, the radius of nth orbit of H-atom is given by

(a) rn²

(b) rn

(c) r/n

(d) r² n²

Answer-(a)

Question-Bohr’s model is not able to account for which of the following.

(a) Stability of atom.

(b) Spectrum of neutral helium atom.

(c) Energy of free electron at rest.

(d) Calculation of radii of the stationary states.

Answer-(b)

Question-If electron, hydrogen, helium and neon nuclei are all moving with the velocity of light, then the wavelength associated with these particles are in the order

(a) Electron > hydrogen > helium > neon

(b) Electron > helium > hydrogen > neon

(c) Electron < hydrogen < helium < neon

(d) Neon < hydrogen < helium < electron

Answer-(a)

Question- Heisenberg's uncertainity principle is applicable to

(a) atoms only

(b) electron only

(c) nucleus only

(d) any moving object

Answer-(d)

Question-In which of the following Bohr’s stationary state, the electron will be at maximum distance from the nucleus ?

(a) IInd

(b) Ist

(c) Vth

(d) IIIrd

Answer-(c)

Question-The orientation of an atomic orbital is governed by

(a) Spin quantum number

(b) Magnetic quantum number

(c) Principal quantum number

(d) Azimuthal quantum number

Answer-(b)

Instructions:

1. All questions are compulsory.

2. Please give the explanation for the answer where applicable.

Q1 -Find the wavelength of radiation emitted when an electron from infinity falls to stationary state 1 in a hydrogen atom. (RH = 1.09 x 107 m^-1) 

Q2 - Explain Hund’s rule with the help of example of nitrogen. 

Q3 - Derive de Broglie’s relationship. What is its significance? 

Q4 - The frequency of a radiation is 6 x 10¹⁴ cycles / sec. Find out the wavelength of radiation in nanometer. 

Q5 - An isotope of atomic mass 27 has 14 neutrons in the nucleus. What is the atomic number, name and symbol of element. 

Q6 - Write the designation for orbitals with following quantum numbers-

(a) n = 3, l = 1 (b) n = 5, l = 2 

Q7 - Who discovered neutrons? 

Q8 - Which element does not have any neutron in it? 

Q9 - Give two examples from everyday life where cathode ray tubes are used? 

Please refer to the link below for CBSE Class 11 Chemistry Structure Of Atom Worksheet Set B