ECAT Pre Engineering Chemistry Chapter 5 MCQ Test With Answer

Effective magnetic moment of Sc³⁺ion is

• 1.73 A
• 0 B
• 5.92 C
• 2.83 D

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

• 3p A
• 3d B
• 3f C
• 3s 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

Which of the following orbitals have a dumb bell shape?

• s A
• p B
• d C
• f D

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

• H A
• Li⁺ B
• Na C
• He⁺ 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

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

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

E = hv is the

• Spectral equation A
• Plank's equation B
• de Broglie's equation C
• None of these D

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

Heaviest particle is

• Meson A
• Neutron B
• Proton C
• Electron D

When the 6d orbital is completed the entering electron goes into

• 7f A
• 7 s B
• 7 p C
• 7 d D

The charge of an electron is determined by

• J.J. Thomson A
• Crooks B
• Perrin C
• R.A.Millikan D

Which of the following element's outermost orbits last electron has magnetic quantum number m=0?

• Na A
• O B
• Cl C
• N D

Which one of the following statements is true about discovery of neutrons?

• These particles were formed by the bombardment of Alpha-particles on Beryllium. A
• These particles are formed by the spiting of alpha-particles. B
• These particles were discovered by natural radioactivity. C
• None of above. D

The ratio of the ionization energy of H and Be³⁺is

• 1 : 1 A
• 1 : 3 B
• 1 : 9 C
• 1 : 16 D

Orbital having same energy is called:

• Hybrid orbital. A
• Valence orbital. B
• Degenerate orbital. C
• D-orbital. D

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

• H A
• Na B
• He⁺ C
• Li⁺ 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

Which have better penetrating power

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

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

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

When potassium metal is exposed to violet light

• Ejection of electrons takes place A
• Ejection of some potassium atoms occurs B
• There is no effect C
• The absorption of electrons takes place 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

Find the magnetic moment of a divalent ion in aqueous solution if its atomic number is 25

• 3.0 BM A
• 4.9 BM B
• 5.9 BM C
• 6.9 BM D

The value of Plank's constant 'h' is

• 6.625 x 10^-34 A
• 6.625 x 10^-34J sec B
• 6.625 x 10^-34KJ C
• 6.625 x 10^-34K Cal 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

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

Negatively charged particle nature of cathode rays was first demonstrated in 1895 by:

• Millikan. A
• J. Perrin. B
• Hittrof C
• J.J. Thomson. D