ECAT Pre Engineering Chemistry Chapter 5 MCQ Test With Answer

When 3p orbital is complete, the entering electron goes into

• 4s A
• 3d B
• 4p C
• 4f 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 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

The quantum number which determines the shape of the orbital is

• principal A
• azimuthal B
• magnetic C
• spin D

With increasing principle quantum number, the energy difference between adjacent energy levels in H atom

• Decreases A
• Increases B
• Remains constant C
• Decreases for low value of Z and increase for higher value of Z D

A 4f orbital has

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

Pauli's principle is applicable to

• Degenerate orbits A
• Two electrons in the same orbital B
• One electron C
• None D

The energy of the first electron is helium will be

• -13.6 eV A
• -54.4 eV B
• -5.44 eV C
• zero D

Azimuthal quantum number of last electron of ₁₁Na is

• 1 A
• 2 B
• 3 C
• 0 D

An orbital can accommodate maximum two electrons with opposite spins according to

• Heisenberg's principle A
• Aufbau principle B
• Hund's srule C
• Pauli exclusion principle 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

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

• 24 A
• 12 B
• 13 C
• 8 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

The credit of discovering neutron goes to

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

The uncertainty principle was stated only

• De Brogilie A
• Heinsenberg B
• Einstein C
• Schrodinger D

• s A
• p B
• d C
• f 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

Which is not true with respect to cathode rays?

• A stream of electrons A
• Charged particles B
• Move with speed as that of light C
• Can be deflected by magnetic fields D

Subsidiary quantum number specifies

• size of orbital A
• shape of orbital B
• orientations of orbitals C
• Nuclear stability 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

Rutherford's experiment led to the discovery of

• Nucleus A
• Electron B
• Proton C
• alpha particle 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

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

Which of the following is not charged particle

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

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

The radiations with wavelength shorter than violet light are called

• Ultraviolet A
• Infrared B
• Microwave C
• Radio frequency 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

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 spectrum of He is expected to be similar to that of

• H A
• Na B
• He⁺ C
• Li⁺ D