How many triads could Dobereiner identify from the elements known at that time?
  • 3
  • 5
  • 4
  • 2
Newlands classification of elements did not include _______ .
  • Metalloids
  • Metals
  • Noble gases
  • Non-metals
Dobereiner's triad arranged the elements with similar properties into:
  • Periods
  • Groups
  • Both period and group
  • None of these
X (atomic mass = 37), Y (atomic mass = 81), and Z are three members of Dobereiner's triads. Atomic mass of Z=?
  • 59
  • 125
  • 130
  • None of the above
Mendeleev's classification was based on _______ .
  • Increasing atomic mass
  • Decreasing atomic number
  • Increasing atomic number
  • Decreasing atomic mass
The Law of Octaves was applicable only upto element ________.
  • Sodium
  • Calcium
  • Zinc
  • Copper
Which of the following triads is a Dobereiner's Triad?
  • N, P, As
  • S, O, H
  • Na, Ra, Al
  • Li, Na, K
How many elements did Mendeleev's periodic table contain?
  • 63
  • 17
  • 58
  • 118
Choose the incorrect statement in view of Mendeleev's Periodic Table.
  • Position of hydrogen was clear.
  • Atomic masses were not strictly followed.
  • Isotopes of elements were placed at same position.
  • Elements were arranged in order of their atomic masses
How many elements were known when Mendeleev started his work on his periodic table?
  • 63
  • 55
  • 69
  • 45
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