ECAT Pre Engineering Chemistry Chapter 5 MCQ Test With Answer

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

Charge of an electron is:

• 1.6 x 10^-19 C

  A

• 9.1 x 10^-34 C

  B

• 1.7588 x 10¹¹ C

  C

• 6.62 x 10^-34 C

  D

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

• 14 A
• 10 B
• 8 C
• 4 D

Subsidiary quantum number specifies

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

Smallest charge of electricity that has been measured so far is

• Charge on a-rays A
• Charge on electron (1.602 x 10^-19C) B
• Charge on x-rays C
• Charge on gamma rays 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

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

Which of the following particles has longest wavelength, if they have same speed:

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

Which have better penetrating power

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

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

• Neutron. A
• Proton. B
• Electron. C
• Positron. 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 valence orbital configuration of an element with atomic number 23 is

• 3d⁵ A
• 3d³, 4s² B
• 3d³, 4s¹, 4p¹ C
• 3d²,4s²,4p¹ D

A 4f orbital has

• one node A
• two node B
• three node C
• four nodes 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 atoms has 1s², 2s², 2p_x²2p¹_y2p¹_zconfiguration

• Nitrogen A
• Carbon B
• Fluorine C
• Oxygen 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

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

n + l value for 4f will

• 2 A
• 5 B
• 7 C
• 9 D

The mass of the neutron is of the order of

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

No cathode rays are produced in the discharged tube when gas is under ordinary pressure even if voltage of 5000 to 10000 is applies. This reason is

• Voltage is low A
• Discharge tube is not coloured B
• Gas does not conduct current under ordinary pressure C
• Temperature low D

e/m of cathode rays is same but for positive rays e/m changes by changing gas in the discharge tube because

• Cathode rays are small sized particles A
• Cathode rays have same charge B
• Nature of cathode rays same for all gasses, but masses of nuclei are different for different gases C
• Temperature of cathode rays higher D

The uncertainty principle was stated only

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

Rutherford's atomic model suggests the existence of

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

Spectrum of white light is continuous becuase

• Colors separated by dark spaces A
• There are no boundary lines between the colours B
• The radiations are in infrared region C
• The radiatins fall in ultraviolet region D

The divisibility of atom was shown by

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

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

• l A
• n B
• m C
• s D

Cathode rays emitted from cathode are

• Canal rays A
• Protons B
• Electrons C
• Positrons D