ECAT Pre Engineering Chemistry Chapter 5 MCQ Test With Answer

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

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

When 6d orbital is complete, the entering electron goes into:

• 7f. A
• 7s. B
• 7p. C
• 7d. D

Cathode rays drive a small paddle wheel placed in their path. This observation shows that

• Cathode rays travel in straight lines A
• Cathode rays are negatively charged B
• Cathode rays produce x-rays C
• Cathode rays are material particles having momentum D

Energy of electron in first orbit of H atom is

• -45.32 KJ/mole A
• -82.08 KJ/mole B
• -52.53 KJ/mole C
• -1313.31 KJ/mole 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

• Plank's equations A
• de Broglie's equations B
• Heisenburg's equation C
• None D

The nature of positive ray depend on:

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

E = hv is the

• Spectral equation A
• Plank's equation B
• de Broglie's equation C
• None of these D

If the radius of first Bohr orbit be a_o, then the radius of third Bohr orbit would be

• 3 x a_o A
• 6 x a_o B
• 9 x a_o C
• 1/2 x a_o D

The symbol of the element whose atoms have the outer most electronic configuration 2s²2p³is

• N A
• Li B
• P C
• Na D

The orbitals having n + l = 5 are

• 2p, 3d,3s A
• 3p, 3d, 5s B
• 3s, 4p, 4d C
• 5s, 4p, 3d 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 experimental evidences for the existence of atomic nucleus comes from:

• Line spectrum of hydrogen. A
• Magnetic bonding of cathode rays. B
• Millikan oil drop experiment. C
• Scattering of alpha particles by thin metal foil. D

The configuration 1s²2s²2p⁵3s¹shows

• Excited state of O₂ A
• Excited state of neon B
• Excited state of fluorine C
• Ground state of fluorine atom D

Photons of yellow colour are ______ energetic than violet colour

• More A
• Less B
• Equal C
• None D

Charge to mass ratio of electron was discovered by:

• Millika. A
• Rutherford. B
• J.J. Thomson. C
• Chadwick. D

Proton was discovered by:

• Chadwick A
• J.J. Rhomson B
• Millikan. C
• Goldstein. D

The total number of possible values of magnetic quantum number for the value of l=3 is

• 3 A
• 1 B
• 5 C
• 7 D

Charge on electron was discovered by:

• Millikan. A
• Crook. B
• Neil Bohr. C
• Rutherford. D

Rutherford's atomic model suggests the existence of

• Atom A
• Nucleus B
• alpha particle C
• Measons D

Heaviest particle is

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

Consider the ground state of Cr atom (Z=24). The numbers of electrons with the azimuthal quantum numbers l = 1 and l = 2 are respectively

• 12 and 4 A
• 16 and 5 B
• 16 and 4 C
• 12 and 5 D

The mass of the neutron is of the order of

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

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

When cathode rays strike the anode metal X-rays are emitted and not the positive rays because

• Cathode rays are material particles A
• Cathode rays knock out electrons from anode, which emit X-rays when outer electron take their place B
• Cathode rays are absorbed by the nucleus C
• Cathode rays become heated D

Azimuthal quantum number of last electron of ₁₁Na is

• 1 A
• 2 B
• 3 C
• 0 D

Find the magnetic moment of a divalent ion in aqueous solution if its atomic number is 25

• 3.0 BM A
• 4.9 BM B
• 5.9 BM C
• 6.9 BM D

Negatively charged particle nature of cathode rays was first demonstrated in 1895 by:

• Millikan. A
• J. Perrin. B
• Hittrof C
• J.J. Thomson. D

The maximum number of electrons in a subshell for which l = 3 is

• 14 A
• 10 B
• 8 C
• 4 D