Test: Discovery Of Sub - Atomic Particles


15 Questions MCQ Test Chemistry Class 11 | Test: Discovery Of Sub - Atomic Particles


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This mock test of Test: Discovery Of Sub - Atomic Particles for Class 11 helps you for every Class 11 entrance exam. This contains 15 Multiple Choice Questions for Class 11 Test: Discovery Of Sub - Atomic Particles (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Discovery Of Sub - Atomic Particles quiz give you a good mix of easy questions and tough questions. Class 11 students definitely take this Test: Discovery Of Sub - Atomic Particles exercise for a better result in the exam. You can find other Test: Discovery Of Sub - Atomic Particles extra questions, long questions & short questions for Class 11 on EduRev as well by searching above.
QUESTION: 1

Which of the following statements is not correct about the characteristics of cathode rays?

Solution:

e/m ratio does not change by changing the gas filled in discharge tube hence characteristics of cathode rays are independent of the gas filled in cathode ray tube. 

QUESTION: 2

The number of radial nodes for 3p orbital is __________.

Solution:

Number of radial nodes = n-1 – 1
For 3p orbital, n = 3 – 1 – 1 = 1
Number of radial nodes = 3 – 1 – 1 = 1. 

QUESTION: 3

Principle Quantum number describes?

Solution:

The principle quantum number serves to determine the size of the orbital, or how far the electron extends from the nucleus.  The higher the value of n the further from the nucleus we can expect to find it.  As n increases so does the energy required as well because the further out from the nucleus you go the more energy the electron must have to stay in orbit.  

QUESTION: 4

The atoms of different isotopes of same element differ from each other in the number of

Solution:

Isotopes of an element will contain the same number of protons and electrons but will differ in the number of neutrons they contain. In other words, isotopes have the same atomic number because they are the same element but have a different atomic mass because they contain a different number of neutrons.

QUESTION: 5

An element has 18 electrons, and 20. neutrons. Its charge is -2. What is its mass number?

Solution:

mass no.=no. of proton+no. of neutron

here no. of proton is 2 less than no. of electron as the charge on element is -2

hence no. of proton=18-2=16,

no. of neutron =20

hence mass number is 16+20=36

QUESTION: 6

The radius of the nucleus of an atom is approximately:

Solution:

A general fact.

QUESTION: 7

Thomson’s plum pudding model explained:

Solution:

Postulates of Thomson’s atomic model
- An atom consists of a positively charged sphere with electrons filled into it. The negative and positive charge present inside an atom are equal and as a whole, an atom is electrically neutral.
- Thomson’s model of the atom was compared to plum pudding and watermelon. He compared the red edible part of the watermelon to positively charged sphere whereas the seeds of watermelon to negatively charged particles.

QUESTION: 8

Which of the following conclusions could not be derived from Rutherford’s α -particle scattering experiment?

Solution:

The conclusions drawn by alpha ray scattering experiment of Rutherford are:
1.Most of the space inside the atom is empty because most of the alpha-particles passed without getting deflected.
2.Very few particles were deflected from their path, indicating that the positive charge of the atom occupies very little space.
3.A very small fraction of alpha-particles were deflected by 180°, this indicates that all the positive charge and mass of the gold atom were concentrated in a very small volume within the atom.

QUESTION: 9

Which model describes that there is no change in the energy of electrons as long as they keep revolving in the same energy level and atoms remains stable?

Solution:
QUESTION: 10

Atomic mass of an element is equal to the sum of?

Solution:

Atomic Mass is the sum of no. of protons and neutrons.

QUESTION: 11

The charge on electron was determined by

Solution:

The charge on electron was determined by milliken by using oil drop experiment

QUESTION: 12

The nature of positive rays depends on?

Solution:

The positive charges in these rays, other than negative cathode rays (which are electrons), depend on the gas that is used because they are cations - atoms with mostly one electron missing and thus one positive charge. So, if you accelerate, argon cations and protons over the same electric potential, the particles in the rays will have the same kinetic energy, but the argon ions will be much slower, as they are much heavier than the protons.

QUESTION: 13

The nucleus of a tritium atom, 3H, contains

Solution:

Tritium (3H) is a radioactive isotope of hydrogen. The nucleus decays (by emittingan electron and an antineutrino), changing from a triton (one proton and two neutrons) to a 3He nucleus (two protons and one neutron).

QUESTION: 14

Which of the following is true about electron:

Solution:

electron carries unit negative charge and has a mass of 9.1 * 10-31 , while proton has a mass of 1.67 * 10-27.

QUESTION: 15

Neutron is a fundamental particle which carries?

Solution:

A neutron is a sub-atomic particle with no net electrostatic charge, with a very similar mass to a proton.