ECAT Pre Engineering Chemistry Chapter 5 MCQ Test With Answer

Rutherford's model of atom failed because:

• The atom did o have a nucleus and electrons A
• It did not account fro the attraction b/w protons and neutrons B
• It did no account for the stability of the atom. C
• There is actually no space b/w the nucleus ad the electrons. 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

Positive particle in discharged tube is produced by ionization of gas molecules, which is caused by

• Gas molecules collide with anode A
• Gas molecules are at high temperature B
• Gas molecules produce X-rays C
• Cathode rays remove electrons from gas molecules D

The orbital in Rutherford's model is

• Spiral A
• Circular B
• Both 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

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

• 3p A
• 3d B
• 3f C
• 3s D

Splitting of spectral lines of the hydrogen atom under the influence or magnetic field is called

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

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

• 
  A
• 
  B
• 
  C
• 
  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 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

Which of the following is not a property of cathode rays

• They can produce x-rays when they strike a heavy metal anode A
• They can cause reduction reaction B
• They produce fluorescence in rare earth and minerals C
• They comprise neutral particles D

The quantum number which describe the orientation of the orbitals is

• Spin quantum number A
• Principle quantum number B
• Azimathal quantum number C
• Magnetic quantum number D

1 erg of energy corresponds to

• 6.02 x 10²³J/mol A
• 6.02 x 10¹⁶J/mol B
• 1 erg/mol C
• 10^-7J/mol D

Which one of the following particles has amass 1/1836 time, that of hydrogen?

• Neutron. A
• Proton. B
• Electron. C
• Positron. 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

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

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

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

When electron jumps from n₂= 2,3,4,5,.... orbit to n₁= 1 orbit in the hydrogen atom, the radiations emitted give the spectral lines

• Lyman series A
• Blamer series B
• Paschen series C
• Brackett series D

The divisibility of atom was shown by

• Stoney A
• J.J. Thomson B
• Millikan C
• Rutherford 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

Neutrons was discovered by

• Mosely A
• Milliken B
• Chadwick C
• Ruherford 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

Neutron was discovered by:

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

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

Which quantum number is sufficient to describe the electron is hydrogen atom?

• l A
• n B
• m C
• s 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

The principle quantum number describes

• The distance form the nucleus A
• The shape of the orbital B
• The orientation of the orbital C
• The spin of the electron 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

The limiting line of Blamer series in hydrogen spectrum lies in

• Visible regions A
• Ultraviolet region B
• Infrared region C
• x-rays region D