Question

Statement A: Valency is always equal to the number of valence electrons in an atom.

Statement R: The oxygen atom has six electrons, it shows a valency of 2.

• A. If 'A' and ‘R’ are true and 'R' is the correct reason for 'A'.
• B. If 'A' and ‘R’ are true but 'R' is not the correct reason for 'A'.
• C. If 'A' is correct and 'R' is wrong.
• D. If 'A' is wrong and ‘R’ is correct.

Answer 1

The correct option is D

If 'A' is wrong and ‘R’ is correct.

• The number of electrons present in the valence shell (outermost shell) of an atom is known as valence electrons.
• While Valency is defined as the number of electrons gained or lost by an atom during the formation of a chemical bond to attain a stable noble gas configuration.
• It can be positive, negative, or zero.
• Hence, valency may or may not be equal to the valence electrons.
• For example - Oxygen has atomic number 8 and its electronic configuration of 2, 6. That means it has 6 electrons in its valence shell.
• But the loss of 6 electrons is difficult hence, oxygen gains two-electron to acquire a stable noble gas configuration.
• Hence, 'A' is wrong and ‘R’ is correct.
• Hence option D is correct.