Olympiad – Class X – Science - Che - Periodic Classication of Elements

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Question - 1

Why are elements classified?

  • A To enable a better understanding on fundamental properties of elements
  • B To find a place for each element and know about its relationship with other elements.
  • C To understand each element in a better way based on various observations.
  • D All of the above

Question - 2

Three elements P,Q, R form a Dobereiner triad. The atomic weights of P and Rare 35 and 127 respectively. Find the atomic weight of Q

  • A 40
  • B 60
  • C 81
  • D 120

Question - 3

The arrangement of elements in the modern periodic table is based on their

  • A electronic configuration
  • B atomic size
  • C atomic number
  • D atomic mass.

Question - 4

Which one of the following is a Dobereiner triad?

  • A C, Mg and Na
  • B 0, N and \(cl\) 
  • C Li, Na and K
  • D Fe, Cu, Zn

Question - 5

Three elements X, Y and Z form a Dobereiner triad. Their atomic weights are in the ratio 5:11:17. If the sum of the atomic weights of extreme elements is 176, then find the atomic weights of X,Y and Z.

  X Y Z
a) 40 80 176
b) 40 88 136
c) 40 80 120
d) 80 100 120
  • A 40 80 176
  • B 40 88 136
  • C 40 80 120
  • D 80 100 120

Question - 6

Which period is the longest in the periodic table?

  • A Third
  • B Fourth
  • C Sixth
  • D Seventh

Question - 7

Which elements in the periodic table are chemically inactive?

  • A Representative elements
  • B Inert gases
  • C Transitional elements
  • D Inner transitional elements

Question - 8

Find the atomic number of an element belonging to group IA and the 3rd period in the periodic table.

  • A 3
  • B 11
  • C 19
  • D 20

Question - 9

Which of the given elements have incompletely filled outermost shells?

  • A Halogens
  • B Transitional elements
  • C Representative elements
  • D Noble gases

Question - 10

According to Modern periodic law, the properties of elements are the periodic functions of 'X: Identify 'X:

  • A Atomic masses of elements
  • B Atomic volumes of elements
  • C Atomic numbers of elements
  • D Densities of elements.