Given below are the CBSE Structure of atoms class9 test Paper
(a) Very Short questions
(b) Short questions
(c) Long answer questions
(d) Foundation/Olypmpiad/JEE/NEET
Hope you like them and do not forget to like , social share and comment at the end of the page.
Very Short Answer Questions
Question 1.
Name the scientist who discovered proton.
Answer
E.Goldstein
Question 2.
What is the approximate ratio of diameters of atom to that of its nucleus?
Answer
Nuclear radius =$10^{-15}$ m
Atomic radius =$10^ {-10}$ m
Ratio of atom to Nuclear= $10^{5}$
Question 3.
What are nucleus? Question 4.
What are isotopes?
Answer
Isotopes are atoms of the same element, which have different mass numbers
Question 5.
Neutrons can be found in all atomic nuclei except in one case. Name this atomic nucleus.
Answer
Hydrogen
Question 6.
What did Rutherford’s alpha- particle scattering experiment prove?
Answer
(a)Most of the space inside the atom is empty because most of the alpha-particles passed through the gold foil without getting deflected.
(b)Very few particles were deflected from their path, indicating that the positive charge of the atom occupies very little space.
Question 7.
An atom contains five protons and six neutrons. What is ts atomic number and mass number?
Answer
Atomic number=5
Mass number=5+6=11
Question 8.
If the number of electrons in an atom 8 and number of protons are also 8. Their atomic number of atom will be eight or zero?
Answer
8
Question 9.
Write the symbol of a element ‘X’ having atomic number ‘Z’ and mass number ‘A’.
Answer
ZAX
Question 10.
For which element is the atomic mass is same as that of a proton?
Answer
Hydrogen
Question 11.
Who discovered the phenomenon of radioactivity?
Answer
Henry Becquerel
Short Answer Questions
Question 1.
How is atomic mass related to the number of protons and number of neutrons? Question 2.
What are valence electrons? Question 3.
What happens when cathode rays strike the glass walls of the cathode ray tube? Question 4.
State Bohr- Bury rules for the distribution of electrons in different energy levels. Question 5.
What is meant by electronic configurations of an element? Question 6.
What is carbon dating? Question 7.
What experiment results into failure of Thomson’s model of the atom as an intimate mixture of negative and positive particles. Question 8.
The magnitude of the charge on the electron is 4.8 x 10-10 e.s.u. what is the magnitude of the charge
(a)On the proton
(b)On the nucleus of He atom Question 9.
Which experiment led to the discovery of neutrons? Question 10.
From amongst K, L, M and N shells, which is associated with lowest energy and which one is associated with highest energy? Question 11.
A element ‘A’ has mass number 24 and contain 12 neutrons. What is the valency of ‘A’? Question 12.
What are the similarities between various isotopes? Question 13.
For each isotope give the composition of its nucleus.
28/14Si, 29/14Si,30/14Si
Long Answer Questions
Question 1.
Write five applications of radioisotopes. Question 2.
Write conclusion of Rutherford’s scattering expperimant. Also mention drawbacks of Rutherford’s model of atom. Question 3.
Name the model of atom proposed to explain the objections raised for Rutherford’s model. Explain this model of atom in detail. Question 4.
A neutral atom of an element has 2K, 8L and 5M electrons. Find out the following from the data:
(a)Atomic number
(b)Total number of s- electron
(c)Total number of p- electrons
(d)Number of protons in the nucleus and
(e)Valency of the element
Answer
(a)It is given the number of electrons in the shells is given as 2 in K shell, 8 in L shell and 5 in the M shell.
Therefore the atom has in total of 2+8+5=15 electrons.
So, Atomic Number is 15
This means that the atom is phosphorus.
The electronic configuration will be as follows.
1s2,2s2, 2p6, 3s s2,3p 3
(b)Total Number of S electron: 6
(c)Total Number of P electron: 9
(d)Number of Protons =Number of electrons=15
(e) Outermost orbit has 5 electrons,So valency can be 3 or 5
Question 5.
Give the electronic configuration of the following ions:
(a)N3
(b)S2-
(c)Cu2+
(d)Cr3+
(e)Fe2+ Question 6.
Name two elements which have isotopes. Write the symbol of their isotopes and provide an account of the sub-atomic particles present in each of these isotopes. Question 7.
Calculate the number of electrons, protons and neutrons in an atom of an element with atomic number 20 and mass number 40. Write electronic configuration and draw the structure of the atom? Question 8.
An atom has complete K and L shells. Is this an atom of a metal, non-metal or noble gas? Justify?
Foundation/Olypmpiad/JEE/NEET Level
Question 1.
Write 4 ponts of difference between cathode rays and anode rays. Question 2.
Explain the principle of carbon dating. Question 3.
How does artificial transmutation differ from artificial radioactivity? Question 4.
Complete the following nuclear reactions:
(a)9642Mo(.., n) 9743Tc
(b) ..(α, 2n) 21185At
(c)24696Cm + 126C -> .... + 4 (10n) Question 5.
Write the nuclear reactions for the following: 23892U undergoes alpha-decay 23491Pa undergoes Beta-decay Question 6.
Arrange alpha, Beta and gamma-rays in the following order
(a)Increasing penetrating power
(b)Decreasing power to ionize gases
(c) Increasing extant of deflection by a magnetic field Question 7.
How are the nucleons held together? Question 8.
Write a note on the nuclear fusion. Question 9.
Which radiations emitted by the radioactive substance have little effect on photographic plate or ZnS screen? Question 10.
In the neutron induced fission reaction of 235/92U, one of the products is 95/36Kr. In this mode another nuclide and three neutrons are also produced.Identify the other nuclide. Question 11.
What disadvantages do protons and a- particles have as nuclear projectiles? Question 12.
What advantages do protons have over a- particles as nuclear projectiles? Question 13.
What kind of elementary particles are used in artificial transmutation of elements? Question 47.
Which isotope of uranium is used in nuclear reactor?
Summary
This Structure of atoms class9 test Paperwith answers is prepared keeping in mind the latest syllabus of CBSE . This has been designed in a way to improve the academic performance of the students. If you find mistakes , please do provide the feedback on the mail.
