Class 10 Science

Periodic Classification of Elements

NCERT Exemplar Problems


Question 19: What type of oxide would Eka– aluminium form?

  1. EO3
  2. E3O2
  3. E2O3
  4. EO
    Answer: (c) E2O3

Question 20: Three elements B, Si and Ge are

  1. Metals
  2. Non-metals
  3. Metalloids
  4. Metal, non-metal and metalloid respectively
    Answer: (c) Metalloids

Question 21: Which of the following elements will form an acidic oxide?

  1. An element with atomic number 7
  2. An element with atomic number 3
  3. An element with atomic number 12
  4. An element with atomic number 19
    Answer: (a) An element with atomic number 7

Question 22: Which one of the following depicts the correct representation of atomic radius(r) of an atom?

Atomic Radii
  1. (i) and (ii)
  2. (ii) and (iii)
  3. (iii) and (iv)
  4. (i) and (iv)
    Answer: (b) (ii) and (iii)

Question 23: Which one of the following does not increase while moving down the group of the periodic table?

  1. Atomic radius
  2. Metallic character
  3. Valence
  4. Number of shells in an element
    Answer: (c) Valence

Question 24: On moving from left to right in a period in the periodic table, the size of the atom.

  1. Increases
  2. Decreases
  3. does not change appreciably
  4. first decreases and then increases
    Answer: (b) Decreases

Question 25: Which of the following set of elements is written in order of their increasing metallic character?

  1. Be Mg Ca
  2. Na Li K
  3. Mg Al Si
  4. C O N
    Answer: (a) Be Mg Ca

Question 26: The element with atomic number 14 is hard and forms acidic oxide and a covalent halide. To which of the following categories does the element belong?

  1. Metal
  2. Metalloid
  3. Non-metal
  4. Left-hand side element
    Answer: (b) Metalloid