Given below are the CBSE Structure of atoms class9 test Paper
a) Concepts questions
b) Short questions
c) Very Short questions
d) Long answer questions
Very Short Answer Questions:
1) Name the scientist who discovered proton.
2) What is the approximate ratio of diameters of atom to that of its nucleus?
3)What are nucleus?
4) What are isotopes?
5) Neutrons can be found I all atomic nuclei except in one case. Name this atomic nucleus.
6) What did Rutherford’s alpha- particle scattering experiment prove?
7) An atom contains five protons and six neutrons. What is ts atomic number and mass number?
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?
9) Write the symbol of a element ‘X’ having atomic number ‘Z’ and mass number ‘A’.
10) For which element is the atomic mass is same as that of a proton?
11) Who discovered the neutral particles present in an atom?
12) What conclusion would you derive from the observation, that in Rutherford’s scattering experiment, most of the alpha- particles passed through gold foil without any deflection?
13) Which shell is closest to the nucleus of an atom?
14) Which energy level would accommodate the 17th
15) Select the isotopes from the following?
21/10A; 22/10B; 23/11C; 23/12D
16) Who discovered the phenomenon of radioactivity?
17)Which radiations emitted by the radioactive substance have little effect on photographic plate or ZnS screen?
18) 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.
19) What disadvantages do protons and a- particles have as nuclear projectiles?
20) What advantages do protons have over a- particles as nuclear projectiles?
21) What kind of elementary particles are used in artificial transmutation of elements?
22) Which isotope of uranium is used in nuclear reactor?
Short Answer Questions:
1) How is atomic mass related to the number of protons and number of neutrons?
2) What are valence electrons?
3) What happens when cathode rays strike the glass walls of the cathode ray tube?
4) State Bohr- Bury rules for the distribution of electrons in different energy levels.
5) What is meant by electronic configurations of an element?
6) What is carbon dating?
7) What experiment results into failure of Thomson’s model of the atom as an intimate mixture of negative and positive particles.
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
On the proton ?
On the nucleus of He atom ?
9) Which experiment led to the discovery of neutrons?
10) From amongst K, L, M
shells, which is associated with lowest energy and which one is associated with highest energy?
11) A element ‘A’ has mass number 24 and contain 12 neutrons. What is the valency of ‘A’?
12) What are the similarities between various isotopes?
For each isotope give the composition of its nucleus.
28/14Si, 29/14Si, 30/14Si
14) How does artificial transmutation differ from artificial radioactivity?
Name the following processes:
Complete the nuclear reaction expression:
59/27Co (d, p)…………
27/13AI (a, n)………...
Complete the following nuclear reaction equations by supplying the missing information:
23/11Na +……. _____23/12Mg + 1/0n
27/13AI +…….______30/15P + 1/0n
Complete the following nuclear reactions:
96/42Mo (……, n) 97/43Tc
……. (a, 2n) 211/85At
246/96Cm + 12/6C______....... + 4 (1/0n)
Write the nuclear reactions for the following:
238/92U undergoes a-decay
234/91Pa undergoes B-decay
Arrange a, B and y-rays in the following order
a)Increasing penetrating power
b)Decreasing power to ionize gases
c) Increasing extant of deflection by a magnetic field
21) How are the nucleons held together?
22) Write a note on the nuclear fusion.
Long Answer Questions:
1) Write 4 ponts of difference between cathode rays and anode rays.
2) Explain the principle of carbon dating.
3) Write five applications of radioisotopes.
4) Write conclusion of Rutherford’s scattering expperimant. Also mention drawbacks of Rutherford’s model of atom.
5) Name the model of atom proposed to explain the objections raised for Rutherford’s model. Explain this model of atom in detail.
A neutral atom of an element has 2K, 8L and 5M electrons. Find out the following from the data:
Total number of s- electron
Total number of p- electrons
Number of protons in the nucleus and
Valency of the element
Give the electronic configuration of the following ions:
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