ECAT Pre Engineering Chemistry Chapter 5 MCQ Test With Answer

The number of electrons in the M shell of the element with atomic number 24 is

• 24 A
• 12 B
• 13 C
• 8 D

When electrons revolve in stationary orbits

• There is no change in energy level A
• They vecome stationary B
• They are gaining kinetic energy C
• There is increase in energy D

What is the packet of energy called?

• Electron A
• Photon B
• Positron C
• Proton D

Spectrum of white light is continuous becuase

• Colors separated by dark spaces A
• There are no boundary lines between the colours B
• The radiations are in infrared region C
• The radiatins fall in ultraviolet region D

The total number of orbitals possible for the quantum number n is

• n A
• n² B
• 2n C
• 2n² D

• Neutrons are attracted by nucleus A
• Neutrons carry out nuclear reactions B
• Neutrons carry no charge C
• Neutrons are electromagnetic radiations D

n + l value for 4f will

• 2 A
• 5 B
• 7 C
• 9 D

The radius of first orbit of H-atom is

• 4.75 A° A
• 3.84 A° B
• 8.4 A° C
• 0.529 A° D

The wave length of electron as wave is 0.5 nm. What is the wave length in meter

• 5 x 10^-9 A
• 5 x 10^-12 B
• 5 x 10^-6 C
• 5 x 10^-10 D

Orbitals having same energy are called

• Hybrid orbitals A
• Valence orbitals B
• Degenerate orbitals C
• D-orbitals D

Heaviest particle is

• Meson A
• Neutron B
• Proton C
• Electron D

Bohr model of atom is contradicted by:

• Planck's quantum theory A
• Pauli's exclusion theory B
• Heisenberg's uncertainty principle. C
• All of above. D

The orbital in Rutherford's model is

• Spiral A
• Circular B
• Both C
• None D

The nature of the positive rays depend on

• The nature of the electrode A
• The nature of the discharge tube B
• The nature of the residual gas C
• All of the above D

Rutherford's planetary like picture of the atomic modal was defective because

• It did not describe the quantity of positive charge A
• It did not explain the repulsion of protons within the nucleus B
• No empty space between nucleus and the electrons C
• Moving electron should radiate energy D

Which of the following is not charged particle

• Proton A
• Electron B
• Neutron C
• Hydrogen nucleus D

When the electron jumps form second third, fourth orbit to the fist orbit, the transitions are known as

• Balmer series A
• Lyman series B
• Pfund series C
• Brackett series D

A 4f orbital has

• one node A
• two node B
• three node C
• four nodes D

Cathode rays emitted from cathode are

• Canal rays A
• Protons B
• Electrons C
• Positrons D

The number of de-electrons retained in Fe²⁺ (At.No. of Fe = 26) ions is

• 3 A
• 4 B
• 5 C
• 6 D

The rules which describe the distribution of electron in atomic energy levels are Auf-ban principle, Pauli's exclusion principle. Hunds rule. The pauli exclusion principle refers to the

• Orientation of orbital in space A
• Fact that two electrons in the same orbital should have opposite spins B
• Energy of the orbital C
• Spin of the electron D

With the reference of w/m ratio of anode rays, the e/m ratio of cathode rays s:

• Greater. A
• same. B
• Smaller. C
• Not fixed. D

In Millikan method for determination of charge on electron the air in the chamber is ionized by

• Protons A
• Electric field B
• X-rays C
• a - particles D

• s A
• p B
• d C
• f D

The order of distance between the various Bohr orbits is

• r₂- r₁> r₃- r₂> r₄- r₃> ...... A
• r₁> r₂> r₂- r₃> r₄-r₃> ..... B
• r₂-r₁= r₃- r₂= r₄- r₃> ..... C
• r₂- r₁> r₃- r₂< r₄- r₃< .... D

The energy of ionization of an atom is the energy difference between orbital

• 
  A
• 
  B
• 
  C
• 
  D

The mass of the neutron is of the order of

• 10^-23 kg A
• 10^-24kg B
• 10^-26kg C
• 10^-27kg D

The spectrum of helium is expected to be similar to that of

• H A
• Li⁺ B
• Na C
• He⁺ D

In Bohr model of hydrogen atom the distance between adjacent orbits increases away from the nucleus, the energy difference between the orbits

• Increases A
• Decreases B
• Reaming same C
• Orbits coincide D

Neutrons was discovered by

• Mosely A
• Milliken B
• Chadwick C
• Ruherford D