Class 10 Chemistry



Periodic Classification

NCERT Exemplar Problems

Upto which element, the Law of Octaves was found to be applicable

  • Oxygen
  • Calcium
  • Cobalt
  • Potassium
    Answer: (b) Calcium

According to Mendeleev's Periodic Law, the elements were arranged in the periodic table in the order of

  • Increasing atomic number
  • Decreasing atomic number
  • Increasing atomic masses
  • Decreasing atomic masses
    Answer: (c) Increasing atomic masses

In Mendeleev’s Periodic Table, gaps were left for the elements to be discovered later. Which of the following elements found a place in the periodic table later

  • Germanium
  • Chlorine
  • Oxygen
  • Silicon
    Answer: (a) Germanium

Which of the following statement (s) about the Modern Periodic Table are incorrect

  • The elements in the Modern Periodic Table are arranged on the basis of their decreasing atomic number
  • The elements in the Modern Periodic Table are arranged on the basis of their increasing atomic masses
  • Isotopes are placed in adjoining group (s) in the Periodic Table
  • The elements in the Modern Periodic Table are arranged on the basis of their increasing atomic number
  • (i) only
  • (i), (ii) and (iii)
  • (i), (ii) and (iv)
  • (iv) only
    Answer: (b) (i), (ii) and (iii)

Which of the given elements A, B, C, D and E with atomic number 2, 3, 7, 10 and 30 respectively belong to the same period?

  • A, B, C
  • B, C, D
  • A, D, E
  • B, D, E
    Answer: (b) B, C, D

The elements A, B, C, D and E have atomic number 9, 11, 17, 12 and 13 respectively. Which pair of elements belongs to the same group?

  • A and B
  • B and D
  • A and C
  • D and E
    Answer: (a) A and B

Where would you locate the element with electronic configuration 2,8 in the Modern Periodic Table?

  • Group 8
  • Group 2
  • Group 18
  • Group 10
    Answer: (c) Group 18

An element which is an essential constituent of all organic compounds belongs to

  • Group 1
  • Group 14
  • Group 15
  • Group 16
    Answer: (b) Group 14

Which of the following statements about the Modern Periodic Table is correct:

  • It has 18 horizontal rows known as Periods
  • It has 7 vertical columns known as Periods
  • It has 18 vertical columns known as Groups
  • It has 7 horizontal rows known as Groups
    Answer: (c) It has 18 vertical columns known as Groups



Exemplar MCQ 2

Exemplar MCQ 3

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