Olympiad – Class IX – Science - Che - Structure of the Atom

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Question - 1

Which pair of substances given below are isotopes?

  • A \(​​​​_{ 6 }^{ 12 }{ C }\) and \(_{ 6 }^{ 14 }{ C }\)
  • B Carbon dioxide and carbon monoxide
  • C Diamond and graphite
  • D \({ C }_{ 2 }{ H }_{ 4 }\) and \({ C }_{ 3 }{ H }_{ 6 }\)

Question - 2

Which valence shell electron arrangement is that of a metallic element?

  • A 2,1
  • B 2,4
  • C 2,5
  • D 2,7

Question - 3

An element X has two isotopes, which may be represented as \(\\ ^{ 238 }X\) and \(\\ ^{ 235 }X\). How does \(\\ ^{ 238 }X\)differ from \(\\ ^{ 235 }X\)?

  • A \(\\ ^{ 238 }X\)has 3 more protons and 3 more electrons than 235.
  • B \(\\ ^{ 238 }X\)has 3 more protons, but same number of electrons as 235
  • C \(\\ ^{ 238 }X\)has 3 more neutrons, but the electrons or protons are same as 235
  • D \(\\ ^{ 238 }X\)has 3 more protons, but same number of electrons as 235.

Question - 4

An atom of an element contains 17 protons, 18 neutrons and 17 electrons. Which of the following will be the atomic structure of another isotope of this element?

  Protons Neutrons Electrons
(a) 17 20 17
(b) 17 18 16
(c) 18 18 17
(d) 20 18 17
  • A 17-20-17
  • B 17-18-16
  • C 18-18-17
  • D 20-18-17

Question - 5

The diagram given below represents the atom of an element.

Which symbol gives the above information?

  • A \(_{ 4 }^{ 9 }{ Be }\)
  • B \(_{ 4 }^{ 9 }{ F }\)
  • C \(_{ 4 }^{ 9 }{ B }\)
  • D \(_{ 4 }^{ 9 }{ O }\)

Question - 6

What does an atom and an ion of the isotope of sodium \(_{ 11 }^{ 22 }\) Na both contain?

  • A 11 electrons
  • B 12 neutrons
  • C 23 protons
  • D 23 neutrons

Question - 7

What can be deduced from the symbol \(_{ 2 }^{ 4 }\)He?

  • A An atom of helium contains two electrons.
  • B An atom of helium has two protons and four neutrons in its nucleus.
  • C The proton (atomic) number of helium is four.
  • D Helium acts as a diatomic molecule.

Question - 8

Which of the following ions has the same number of electrons as a krypton atom with atomic number 36 ?

  • A Chlorine
  • B Sodium
  • C Rubidium
  • D Xenon

Question - 9

In elements \(_{ 15 }^{ 31 }{ P }\) and \(_{ 16 }^{ 32 }{ S }\) which of the following are the same?

  • A Number of nucleons
  • B Number of electrons
  • C Number of neutrons
  • D Number of protons

Question - 10

What is valency?

  • A The combining capacity of an element
  • B The atomicity of an element
  • C The oxidation number of an element
  • D All of the above