ECAT Pre Engineering Chemistry Chapter 5 MCQ Test With Answer

Energy of electron in the infinite Bohr orbit of H-atom is

• 0 KJ/mole A
• 1 KJ/mole B
• -1 KJ/mole C
• -1313.32 KJ/mole D

The velocity of photon is:

• Independent of its wavelength. A
• Depends on its wavelength. B
• Equal to square of its amplitude C
• Depends on its source. D

The credit of discovering neutron goes to

• Rutherford A
• Langmuir B
• Chadwick C
• Austen D

The radius of second Bohr's orbit is

• 0.053 nm A
• 0.053/4 nm B
• 0.053 x 4 nm C
• 0.053 x 20 nm D

Which of the atoms has 1s², 2s², 2p_x²2p¹_y2p¹_zconfiguration

• Nitrogen A
• Carbon B
• Fluorine C
• Oxygen D

The ratio of the ionization energy of H and Be³⁺is

• 1 : 1 A
• 1 : 3 B
• 1 : 9 C
• 1 : 16 D

Charge to mass ratio of electron was discovered by:

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

The total number of orbitals in a shell with principal quantum number 'n' is

• 2n A
• 2n² B
• n² C
• n + 1 D

The wave number of the line emitted is 109.678 x 10⁵m^-1in the Lyman series when electron transition occurs

• 
  A
• 
  B
• 
  C
• 
  D

The nature of positive rays depend on:

• Nature of discharge tube. A
• Nature of resident gas. B
• Nature of electrode. C
• All of above. D

n + l value for 4f will

• 2 A
• 5 B
• 7 C
• 9 D

Which of the following has more unpaired d-electrons?

• Zn⁺ A
• Fe²⁺ B
• Ni³⁺ C
• Cu⁺ D

Splitting of spectral lines when atoms are subjected to strong electric field is called:

• Zeeman effect. A
• Stark effect B
• Photoelectric effect. C
• Compton effect. D

An electron with n = 3 , l = 2 will be in the sub-shell

• 3p A
• 3d B
• 3f C
• 3s D

When 6s orbital is complete then next electron goes to

• 6p A
• 6d B
• 5d C
• 4f 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

Sodium chloride imparts a yellow colour to the Bunsen flame. This can be interpreted due to the

• low ionization energy of sodium A
• sublimation of metallic sodium to give yellow vapour B
• emission of excess energy absorbed as a radiation in the visible region as a radiation in the visible region C
• photosenitivity 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

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

• H A
• Li⁺ B
• Na C
• He⁺ 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

Orbitals having same energy are called

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

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

• N A
• Li B
• P C
• Na D

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

Electrons in degenerate orbitals are placed in separate orbitals with same spin according to

• Hund's rule A
• Pauli exclusion principle B
• Aufbau principle C
• Mosley's law D

The electron in an atom

• moves randomly around the nucleus A
• has fixed space around the nucleus B
• is stationary in various energy levels C
• moves around its nucleus in definite energy levels D

Their e/m, ratio resembles with that of electrons

• Alpha rays A
• Beta rays B
• Gamma rays C
• X-rays D

• s A
• p B
• d C
• f D

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

The value of R (Rydberg's constant) is _______ m-1

• 1.0974 x 107 A
• 1.0842 x 107 B
• 1.082 x 10-7 C
• Both a and b D

In the ground state of an atom the electron is present

• In the nucleus A
• In the second shell B
• Nearest to the nucleus C
• Farthest from the nucleus D