ECAT Pre Engineering Chemistry Chapter 5 MCQ Test With Answer

The credit of discovering neutron goes to

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

Balmer's series is in ______ region

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

The total number of possible values of magnetic quantum number for the value of l=3 is

• 3 A
• 1 B
• 5 C
• 7 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

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

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

Alpha rays consist of:

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

The wave number of the line emitted is 109.678 x 10⁵m^-1in the Lyman series when electron transition occurs

• 
  A
• 
  B
• 
  C
• 
  D

Orbitals having same energy are called

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

The total values of magnetic quantum number of subshell are five, the subshell is

• S-subshell A
• P-subshell B
• D-subshell C
• F-subshell D

The divisibility of atom was shown by

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

The nature of positive ray depend on:

• The nature of electrode. A
• The nature of discharge tube. B
• The nature of residual gas. C
• All of above. 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 e.m value for positive rays maximum for:

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

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

• 7f. A
• 7s. B
• 7p. C
• 7d. D

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

Charge to mass ratio of electron was discovered by:

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

For which of the following sets of quantum numbers and electron will have the highest energy?

• 3,2,1,1/2 A
• 4,2,-1,1/2 B
• 4,1,0,-1/2 C
• 5,0,0,1/2 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

Subsidiary quantum number specifies

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

Rutherford's model of atom failed because:

• The atom did o have a nucleus and electrons A
• It did not account fro the attraction b/w protons and neutrons B
• It did no account for the stability of the atom. C
• There is actually no space b/w the nucleus ad the electrons. D

Rutherford's atomic model suggests the existence of

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

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

The orbital in Rutherford's model is

• Spiral A
• Circular B
• Both C
• None 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

The radius of second Bohr's orbit is

• 0.053 nm A
• 0.053/4 nm B
• 0.053 x 4 nm C
• 0.053 x 20 nm 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