ECAT Pre Engineering Chemistry Chapter 5 MCQ Test With Answer

The third line of the Balmer series, in the emission spectrum of the hydrogen atom,is due to the transition from the

• Fourth Bohr orbit to the first Bohr orbit A
• Fifth Bohr orbit to the second Bohr orbit B
• Sixth Bohr orbit to the third Bohr orbit C
• Seventh Bohr orbit to the third Bohr orbit D

Heaviest particle is

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

Neutrons was discovered by

• Mosely A
• Milliken B
• Chadwick C
• Ruherford D

The wave length of electron as wave is 0.5 nm. What is the wave length in meter

• 5 x 10^-9 A
• 5 x 10^-12 B
• 5 x 10^-6 C
• 5 x 10^-10 D

The range of visible spectrum is

• 300 - 600 nm A
• 600 - 900 nm B
• 400 - 750 nm C
• 100 - 300 nm 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 credit of discovering neutron goes to

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

The nature of the positive rays depend on

• The nature of the electrode A
• The nature of the discharge tube B
• The nature of the residual gas C
• All of the above D

The arrangement of subshells in the ascending order of their energy on complete filing of 4f subshell the entering electrons goes to

• 5s A
• 5p B
• 5d C
• 5f 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

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

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

Splitting of spectral lines when atoms are subjected to strong electron field is called

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

Photons of yellow colour are ______ energetic than violet colour

• More A
• Less B
• Equal C
• None D

When an electric current is passed through discharge tube at low pressure, cathode rays are emitted from cathode these rays consist of:

• Alpha rays. A
• Negative particles. B
• Electromagnetic rays. C
• Positive particles. 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

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

• 7f. A
• 7s. B
• 7p. C
• 7d. D

What is the packet of energy called?

• Electron A
• Photon B
• Positron C
• Proton D

The uncertainty principle was stated only

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

Charge to mass ratio of electron was discovered by:

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

Balmer's series is in ______ region

• Visible A
• U V B
• I. R. C
• None 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

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

The configuration 1s²2s²2p⁵3s¹shows

• Excited state of O₂ A
• Excited state of neon B
• Excited state of fluorine C
• Ground state of fluorine atom 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

Subsidiary quantum number specifies

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

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

Effective magnetic moment of Sc³⁺ion is

• 1.73 A
• 0 B
• 5.92 C
• 2.83 D

Alpha rays consist of:

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