Question: 21. Which of the following elements will form an acidic oxide?
(a) An element with atomic number 7
(b) An element with atomic number 3
(c) An element with atomic number 12
(d) An element with atomic number 19
Answer: (a) An element with atomic number 7
Question: 22. 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?
(d) Left-hand side element
Answer: (b) Metalloid
Question: 23. Which one of the following depicts the correct representation of atomic radius(r) of an atom?
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (iii) and (iv)
(d) (i) and (iv)
Answer: (b) (ii) and (iii)
Question: 24. Which one of the following does not increase while moving down the group of the periodic table?
(a) Atomic radius
(b) Metallic character
(d) Number of shells in an element
Answer: (c) Valence
Question: 25. On moving from left to right in a period in the periodic table, the size of the atom.
(c) does not change appreciably
(d) first decreases and then increases
Answer: (b) Decreases
Question: 26. Which of the following set of elements is written in order of their increasing metallic character?
(a) Be Mg Ca
(b) Na Li K
(c) Mg Al Si
(d) C O N
Answer: (a) Be Mg CaNCERT Solutions of Periodic Classification of Elements Class 10
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