ECAT Pre Engineering Chemistry Chapter 5 MCQ Test With Answer

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

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

Which of the following is not charged particle

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

Energy of electron in first orbit of H atom is

• -45.32 KJ/mole A
• -82.08 KJ/mole B
• -52.53 KJ/mole C
• -1313.31 KJ/mole D

Charge to mass ratio of electron was discovered by:

• Millika. A
• Rutherford. B
• J.J. Thomson. C
• Chadwick. D

The atomic number of an element is 35 what is the total number of electrons present in all the p-orbitals of the ground state atom of that element?

• 6 A
• 11 B
• 17 C
• 23 D

Alpha rays consist of:

• Neutrons. A
• Helium nucleus. B
• Protons. C
• Hydrogen nucleus. 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

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 6s orbital is complete then next electron goes to

• 6p A
• 6d B
• 5d C
• 4f D

Which of the following is not a sub-atomic particle

• Electron A
• Proton B
• Neutron C
• Deuteron 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 correct set of quantum numbers (n,l and m) respectively of the unpaired electron of chlorine atom is

• 2,1,0 A
• 2,1,1 B
• 3,1,1 C
• 3,2,1 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 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

The experimental evidences for the existence of atomic nucleus comes from:

• Line spectrum of hydrogen. A
• Magnetic bonding of cathode rays. B
• Millikan oil drop experiment. C
• Scattering of alpha particles by thin metal foil. D

The orbitals having n + l = 5 are

• 2p, 3d,3s A
• 3p, 3d, 5s B
• 3s, 4p, 4d C
• 5s, 4p, 3d D

Neutrons was discovered by

• Mosely A
• Milliken B
• Chadwick C
• Ruherford 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

Orbitals having same energy are called

• Hybrid orbitals A
• Valence orbitals B
• Degenerate orbitals C
• D-orbitals 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

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

• Na A
• O B
• Cl C
• N D

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

• H A
• Li⁺ B
• Na C
• He⁺ D

Four d-orbitals contain four lobes while fifth contains only two lobes the orbital is

• dxy A
• dxz B
• dz² C
• dx²- y² D

Effective magnetic moment of Sc³⁺ion is

• 1.73 A
• 0 B
• 5.92 C
• 2.83 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

Light emitted from a source has its wave length 500nm, then its wave number will be

• 2 x 10⁶m^-1 A
• 2 x 10⁷m^-1 B
• 5 x 10⁸ m^-1 C
• 5 x 10⁹m^-1 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

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