IX-SCIENCE-STRUCTURE OF ATOM
(IXS110)
1. There are four atoms A,B,C and D with atomic numbers 9,11,13, and 15,
respectively. The atom containing less than 8 electrons in the second or L-shell is
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A
B
C
E
2. The idea of fixed energy levels in an atom was given by
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The atom consists of a positively charged centre called nucleus
Nucleus consists of protons and neutrons
Most of the mass is concentrated in the nucleus
The volume of nucleus is very small as compared to the total volume of the
atom
6. The nucleus of an atom of phosphorus is represented as 15P31. The number of
protons, neutrons and electrons in the atom of phosphorus are respectively
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X-rays
Cathode rays
Υ-rays
anode rays
5. Which of the following statement is wrong for the model of an atom as proposed by
Rutherford?
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positron
neutron
proton
electron
4. Positive charge is carried by
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E. Rutherford
R.A. Mullikan
Schrodinger
Neils Bohr
3. The nucleus of hydrogen atom is called
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15, 31, 15
15, 15, 16
15, 31, 16
15, 16, 15
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7. When an atom form ions
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no. of proton changes
no. of electron changes
no. of neutron changes
both no. electrons and protons changes
8. What is the definition of nucleon (mass) number?
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has high refractive index
has high density
is highly malleable
is highly ductile
12. Which of the following does not comprise suggestions made by Bohr and Bury
about arrangement of electrons outside the nucleus?
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Ne
Mg2+
Al3+
P3-
11. Gold foil was used in Rutherford's scattering experiment because it
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Hydrogen
Beryllium
Carbon-12
Nitrogen
10. The atomic numbers of neon (Ne), magnesium (Mg2+), aluminium (A13+) and
phosphorus (P3-) are 10, 12, 13 and 15 respectively. Select the odd species in
terms of electronic configuration.
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the mass in grams of an atom
the number of electrons in an atom
the number of nuclei in a molecule
the total number of protons and neutrons in an atom
9. Which of the following elements have the same number of protons and neutrons in
their atom?
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Electrons revolve round the nucleus in fixed orbits
The max. no. of electrons in any shell cannot exceed 2n2
It is absolutely necessary that an orbit has its full quota of electrons before
starting to fill the next
The energy shell are represented by K, L, M, N shells
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13. What is responsible for emission of different colours by different atoms?
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Electronic configuration of atoms
Colour of atoms
Mass of atoms
Ratio of protons to neutrons in the atom
14. Who carried out the discharge tube experiment for the first time?
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Electrons
Protons
Neutrons
Positrons
18. If a neutral atom has three shells completely filled up, then the atomic number of
the atom is
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Bromine isotopes have different numbers of protons.
Bromine contains the two isotopes in equal proportions.
Bromine has different oxidation states.
Bromine is radioactive.
17. Which of the following particles form the anode rays?
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one proton and one electron
one proton only
one proton and one neutron
one electron and one neutron
16. Naturally occurring bromine has a relative atomic mass of 80 and consists entirely
of two isotopes of relative isotopic masses 79 and 81. What can be deduced about
naturally occurring bromine from this information only?
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Crookes
Goldstein
Chadwick
Thomson
15. When one neutron disintegrates, it produces
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1
1
28
16
18
20
19. The maximum number of electrons that can go into the M-shell is ____.
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20. Isotopes contain the same number of ................ but different number of .................
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21. Most of the space in an atom is occupied by ________.
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22. Sulphur exists as four naturally occurring isotopes with mass numbers 32,33, 34,
35 and atomic number 16. (i)Give atomic symbol for each indicating mass number
and atomic number. (ii) Would these have similar physical or chemical properties?
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23. An archaeological sample has only 25% as much carbon-14 as in a living sample.
Knowing that the half-life of carbon-14 is 5800 years, calculate the age of the
sample.
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24. What is the maximum no. of electrons, an M-shell of the atom can accommodate ?
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25. In what field Ernest Rutherford was interested?
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26. What is valency? What is its use?
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27. In Rutherford experiment of scattering of alpha particles, can we take foil of any
other metal instead of gold?
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28. Magnesium atoms has 12 electrons. Which energy shell is incomplete?
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29. What are nucleons?
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30. What is an orbit?
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31. Define valency by taking examples of silicon and oxygen.
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32. State the location of neutrons in an atom.
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33. What do you understand by the term 'radioisotope dating'?
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34. What kind of electronic configuration is attained by chemically inert substances?
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35. If an atom contains one electron and one proton, will it carry any charge or not?
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36. State Hund's rule.
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37. What is the atomic number of an element which has 7 electrons in the M shell?
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38. What do you understand by ‘variable valency’? Give two examples of metals and
two examples of non – metals showing variable valency?
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39. Write the electronic configuration of any one pair of isotopes and isobars?
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40. Where are the valence electrons located in an atom ?
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41. Define electron.
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42. Describe the essential features of the model of atom proposed by E. Rutherford.
How is it different from that proposed by J.J. Thomson?
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