ECAT Pre Engineering Chemistry Chapter 5 MCQ Test With Answer

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

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

If the value of principal quantum number is 3. the total possible values for magnetic quantum number will be

• 1 A
• 4 B
• 9 C
• 12 D

Quantum number values for 2p orbitals are

• n = 2, l = 1 A
• n = 1, l = 2 B
• n = 1, l = 0 C
• n = 2, l = 0 D

Their e/m, ratio resembles with that of electrons

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

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

• 14 A
• 10 B
• 8 C
• 4 D

For principle quantum number n=4, the total number of orbitals having l = 3 is

• 3 A
• 7 B
• 5 C
• 9 D

In Millikan method the oil droplet falls under the force of gravity but it moves upward due to

• Electric field A
• Magnetic field B
• Incident light C
• X-rays D

Mass of simple electron is:

• 9.1 x 10^-31 kg

  A

• 9.1 x 10^-30 kg

  B

• 1.66 x 10^-31 kg

  C

• 9.1 x 10^-31 kg

  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

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

• N A
• Li B
• P C
• Na D

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

• Paschen A
• Pfund B
• Balmer C
• Brackett D

The electronic configuration of an atom/ion can be defined by the following

• Aufbau principle A
• Pauli's exclusion principle B
• Hund's Rule C
• All the above D

The charge over mass ratio of electron is:

• 1.6 x 10^-1 C Kg^-1

  A

• 9.1 x 10^-31 C Kg^-1

  B

• 1.7588 x 10¹¹ C Kg^-1

  C

• 6.62 x 10^-34 C Kg^-1

  D

Which of the following is not isoelectronic?

• Na⁺ A
• Mg²⁺ B
• O^2- C
• Cl^- 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

The mass of the neutron is of the order of

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

The total values of magnetic quantum number of subshell are five, the subshell is

• S-subshell A
• P-subshell B
• D-subshell C
• F-subshell D

Neutron was discovered by:

• Chadwick. A
• Bohr. B
• Rutherford. C
• Plank. D

The wave number of the light emitted by a certain source is 2 x 10⁶m^-1. The wavelength of this light will be

• 500 nm A
• 500 m B
• 200 nm C
• 5 x 10⁷m 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

Quantum number value for 2p orbitals are:

• n=2 ,l=1 A
• n=1 ,l=2 B
• n= ,l=0 C
• n=2 ,l=0 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

Alpha rays consist of:

• Neutrons. A
• Helium nucleus. B
• Protons. C
• Hydrogen nucleus. D

Which of the following was discovered first:

• Charge to mass ratio of electrons. A
• Mass of electrons. B
• Charge of electrons. C
• All of above at same time. D

Azimuthal quantum number of last electron of ₁₁Na is

• 1 A
• 2 B
• 3 C
• 0 D

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

When 6s orbital is complete then next electron goes to

• 6p A
• 6d B
• 5d C
• 4f 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

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

• 24 A
• 12 B
• 13 C
• 8 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