Question 7 - MCQs from (Past Year Papers & NCERT Exemplar) - Chapter 5 Class 10 - Periodic Classification of Elements

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

Metals form basic oxides and non-metals form acidic oxides.

Metals gain electrons to become stable whereas, non-metals lose electrons to become stable.

• Option (a) - Atomic number 7: Electronic configuration is 2, 5
• Option (b) - Atomic number 3: Electronic configuration is 2, 1
• Option (c) - Atomic number 12: Electronic configuration is 2, 8, 2
• Option (d) - Atomic number 19: Electronic configuration is 2, 8, 8, 1

Among the given elements only (a) will gain electrons to become stable and is therefore a non metal. Hence, it will form an acidic oxide.

So, the correct option is (a) Atomic number 7