CBSE Class 11 Chemistry Basic Concepts and Structure Of Atom

Structure Of Atom MCQ Questions with Answers Class 11 Chemistry

Question- Which of the scientist were able to prove that atom is no longer non-divisible?
(a) Dalton
(b) Michael Faraday
(c) Thomson
(d) Chadwick
Answer-(b)

Question-Which of the following is never true for cathode rays ?
(a) They possess kinetic energy.
(b) They are electromagnetic waves.
(c) They produce heat.
(d) They produce mechanical pressure.
Answer-(b)

Question-Cathode rays are deflected by
(a) an electric field only
(b) magnetic field only
(c) by both
(d) by none
Answer-(c)

Question-Which of the following statement is not correct about the characteristics of cathode rays?
(a) They start from the cathode and move towards the anode.
(b) They travel in straight line in the absence of an external electrical or magnetic field.
(c) Characteristics of cathode rays do not depend upon the material of electrodes in cathode ray tube.
(d) Characteristics of cathode rays depend upon the nature of gas present in the cathode ray tube.
Answer-(d)

Question-Which of the following statements about the electron is incorrect?
(a) It is negatively charged particle
(b) The mass of electron is equal to the mass of neutron.
(c) It is a basic constituent of all atoms.
(d) It is a constituent of cathode rays.
Answer-(b)

Question- While performing cathode ray experiments, it was observed that there was no passage of electric current under normal conditions. Which of the following can account for this observation ?
(a) Dust particles are present in air
(b) Carbon dioxide is present in air
(c) Air is a poor conductor of electricity under normal conditions
(d) None of the above
Answer-(c)

Question-Which is not true with respect to cathode rays?
(a) A stream of electrons
(b) Charged particles
(c) Move with speed same as that of light
(d) Can be deflected by magnetic fields
Answer-(c)

Question-What is the optimum conditions required to study the conduction of electricity through gases.
(a) High pressure and low voltage
(b) High pressure and high voltage
(c) Low pressure and high voltage
(d) Low pressure and low voltage
Answer-(c)

Question- In discharge tube experiment stream of negatively charged particles travel from
(a) anode to cathode
(b) cathode to anode
(c) Both (a) and (b)
(d) Electrons does not travel
Answer-(b)

Question-Millikan performed an experiment method to determine which of the following ?
(a) Mass of the electron
(b) Charge of the electron
(c) e/m ratio of electron
(d) Both (a) and (b)
Answer-(b)

Question-The discovery of neutron became very late because :
(a) neutrons are present in nucleus
(b) neutrons are chargeless
(c) neutrons are fundamental particles
(d) all of the above
Answer-(b)

Question-Which is correct statement about proton ?
(a) Proton is nucleus of deuterium
(b) Proton is α-particle
(c) Proton is ionized hydrogen molecule
(d) Proton is ionized hydrogen atom
Answer-(d)

Question-The lightest particle is :
(a) α -particle
(b) positron
(c) proton
(d) neutron
Answer-(b)

Question-When beryllium is bombarded with alpha particles (Chadwick’s experiment) extremely penetrating radiations, which cannot be deflected by electrical or magnetic field are given out. These are :
(a) A beam of protons
(b) Alpha rays
(c) A beam of neutrons
(d) A beam of neutrons and protons
Answer-(c)

Question-Neutron is discovered by
(a) Chadwick
(b) Rutherford
(c) Yukawa
(d) Dalton
Answer-(a)

Question-Which of the following properties of atom could be explained correctly by Thomson Model of atom?
(a) Overall neutrality of atom.
(b) Spectra of hydrogen atom.
(c) Position of electrons, protons and neutrons in atom.
(d) Stability of atom.
Answer-(a)

Question- Rutherford’s experiment on the scattering of α -particles showed for the first time that the atom has :
(a) electrons
(b) protons
(c) nucleus
(d) neutrons'
Answer-(c)

Question-When atoms are bombarded with alpha particles, only, a few in million suffer deflection, others pass out undeflected.This is because
(a) the force of repulsion on the moving alpha particle is small
(b) the force of attraction between alpha particle and oppositely charged electrons is very small
(c) there is only one nucleus and large number of electrons
(d) the nucleus occupies much smaller volume compared to the volume of the atom
Answer-(d)

Question-Rutherford’s α-particle dispersion experiment concludes
(a) all positive ions are deposited at small part
(b) all negative ions are deposited at small part
(c) proton moves around the electron
(d) neutrons are charged particles.
Answer-(a)

Question- Which of the following scientists explained his model on the basis of centrifugal force ?
(a) Thomson
(b) Dalton
(c) Millikan
(d) Rutherford
Answer-(d)

Question- The number of neutrons in dipositive zinc ion with mass number 70 is
(a) 34
(b) 36
(c) 38
(d) 40
Answer-(d)

Question. The orbital angular momentum for an electron revolving in an orbit is given by √l(l + 1). h/2π. This momentum for an s-electron will be given by
(A) +1/2. h/2π
(B) Zero
(C) h/2π
(D) √2 . h/2π
Answer- B

Question. Which of the following set a of quantum numbers is correct for an electron in 4f orbital?
(A) n = 4, l =3, m = +4, s = +1/2
(B) n = 4, l = 4, m = –4, s = –1/2
(C) n = 4, l = 3, m = +1, s = +1/2
(D) n = 3, l=2, m =–2, s = +1/2
Answer- C

Question. Consider the ground state of Cr atom (Z = 24). The numbers of electrons with the azimuthal quantum numbers, l = 1 and 2 are, respectively 
(A) 12 and 4
(B) 12 and 5
(C) 16 and 4
(D) 16 and 5
Answer- B

Question. In a multi-electron atom, which of the following orbitals described by the three quantum numbers will have the same energy in the absence of magnetic and electric field ?
(i) n = 1, l = 0, m = 0 (ii) n =2, l = 0, m = 0 (iii) n = 2, l = 1, m = 1 (iv) n = 3, l = 2, m =1
(v) n = 3, l = 2, m = 0
(A) (iv) and (v)
(B) (iii) and (iv)
(C) (ii) and (iii)
(D) (i) and (ii)
Answer- A

Question. Which of the following statements in relation to the hydrogen atom is correct ? 
(A) 3s, 3p and 3d orbitals all have the same energy
(B) 3s and 3p orbitals are of lower energy than 3d orbital
(C) 3p orbital is lower in energy than 3d orbital
(D) 3s orbital is lower in energy than 3p orbital
Answer- A

Question. Which of the following set of quantum numbers represents the highest energy of an atom ?
(A) n = 3, l = 0, m = 0, s = + 1/2
(B) n = 3, l = 1, m =1, s = + 1/2
(C) n = 3, l = 2, m = 1, s = + 1/2
(D) n = 4, l = 0, m = 0, s = + 1/2
Answer- C

Question. The electrons identified by quantum numbers n and l : 
(a) n = 4, l = 1 (b) n = 4, l = 0 (c) n = 3, l = 2 (d) n = 3, l = 1
can be placed in order of increasing energy as :
(A) (c) < (d) < (b) < (a)
(B) (d) < (b) < (c) < (a)
(C) (b) < (d) < (a) < (c)
(D) (a) < (c) < (b) < (d)
Answer- B

Question. The correct set of four quantum numbers for the valence electrons of rubidium atom (Z = 37) is :
(A) 5, 0, 0, +1/2
(B) 5, 1, 0, +1/2
(C) 5,1, 1, +1/2
(D) 5, 0, 1, +1/2
Answer- A

Question. For a one-electron atom, the set of allowed quantum numbers is : 
(A) n = 1, l = 0, m_l = 0, m_s = +½
(B) n = 1, l = 1, m_l = 0, m_s = +½
(C) n = 1, l = 0, m_l = –1, m_s = –½
(D) n = 1, l = 1, m_l = 1, m_s = –½
Answer- A

Question. The isoelectronic pair of ions is : 
(A) Sc²⁺ and V³⁺
(B) Mn³⁺ and Fe²⁺
(C) Mn²⁺ and Fe³⁺
(D) Ni³⁺ and Fe²⁺
Answer- C

Question. The ion that is isoelectronic with CO is 
(A) O₂⁺
(B) O₂^–
(C) CN^–
(D) N₂⁺
Answer- C

More Question

Q.1 An ion with mass number 56 contains 3 units of positive charge and 30.4% more neutrons than electrons. Assign symbol to this ion.
Q.2. Calculate the energy required for the process:  He⁺ —→He²⁺ +e ^- 
Given, the ionization energy for H-atom in ground state is 2.18 x 10^-18 Jatom^-1.
Q.3. A 100 watt bulb emits monochromatic light of wavelength 400pm. Calculate the number of photons emitted per second by bulb.
Q.4. Calculate the number of electrons present in 1mole of CH₄.
Q.5. Calculate the molarity of solution of ethanol in water in which the mole fraction of ethanol is 0.040.
Q.6. Calculate the volume of dioxygen at S.T.P liberated by heating 12.25g of KClO₃.
Q.7. How many moles of CH₄ are required to produce 22g of CO₂ on combustion?
Q.8. 1M solution of NaNO₃ has density 1.25 gcm^-3. Calculate its molality.

Q.9. Calculate the %age of copper in sample of CuCl₂.