ECAT Pre Engineering Chemistry Chapter 5 MCQ Test With Answer

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

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

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

• 4s A
• 3d B
• 4p C
• 4f D

If the radius of first Bohr orbit be a_o, then the radius of third Bohr orbit would be

• 3 x a_o A
• 6 x a_o B
• 9 x a_o C
• 1/2 x a_o D

The size of electronic shell is described by

• Azimuthal Q. no A
• Magnetic Q.No B
• Spin Q. No C
• Principle Q. No D

Energy of electron in an orbit according to Bohr theory is negative due to

• Repulsion of electrons in the same orb A
• At infinity energy is zero ad a traction towards nucleus decreases energy B
• Electron has negative charge C
• Product of positive nuclear charge and negative charge is negative 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

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

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

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

Neutron was discovered by:

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

Balmer's series is in ______ region

• Visible A
• U V B
• I. R. C
• None D

• s A
• p B
• d C
• f D

The credit of discovering neutron goes to

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

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

• H A
• Na B
• He⁺ C
• Li⁺ 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

When 6d orbital is complete, the entering electron goes into:

• 7f. A
• 7s. B
• 7p. C
• 7d. D

The order of distance between the various Bohr orbits is

• r₂- r₁> r₃- r₂> r₄- r₃> ...... A
• r₁> r₂> r₂- r₃> r₄-r₃> ..... B
• r₂-r₁= r₃- r₂= r₄- r₃> ..... C
• r₂- r₁> r₃- r₂< r₄- r₃< .... D

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

For a 3P subshell the set of principle and azimuthal quantum number is

• n = 1 , l = 2 A
• n = 3, l = 0 B
• n = 3, l = 1 C
• n = 1, l = 3 D

The quantum number which describes the shape of the orbital is

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

The value of charge on electron is

• 1.602 x 10^-19coulombs A
• 1.602 x 10^-18coulombs B
• 1.602 x 10^-17coulombs C
• 1.602 x 10^-16 coulombs D

Photons of yellow colour are ______ energetic than violet colour

• More A
• Less B
• Equal C
• None D

An electron has principal quantum number 3. The number of its 1 subshell and 2 orbitals would be respectively

• 3 and 5 A
• 3 and 7 B
• 3 and 9 C
• 2 and 5 D

The e.m value for positive rays maximum for:

• Oxygen. A
• Nitrogen. B
• Helium. C
• Hydrogen. D

The orbital in Rutherford's model is

• Spiral A
• Circular B
• Both C
• None D

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

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

Electrons arranged in orbitals according to the increasing order of their n + l values, this rule is named as

• Hund's rule A
• Heisenberg's principle B
• Paulit exclusion principle C
• Auf bau principle D

The radiations with wavelength shorter than violet light are called

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

n + l value for 4f will

• 2 A
• 5 B
• 7 C
• 9 D