Question

Which of the following statements is incorrect regarding valency of an element?

(a) Valency of alkali metals is 2

(b) Valency of group 18 elements is zero

(c) Valency of elements first increases till group 14 and then decreases across a period in the Modern Periodic Table.


Only (a)


Only (c)


Only (b)


Both (a) and (c)

Answer 1

Answer:

option A

Explanation:

Alkali metals are found in first group....

and hence their valency is one .i.e.they need to lose just one electron to gain stability

Answer 2

Answer:

The valency of alkali metals is one.

Therefore the option (a) is the incorrect statement regarding the valency.

Explanation:

• Valency of an element shows the tendency of the element to gain or lose the electrons. It also tells about the combining power of an element with other element to form a compound.
• Valency of alkali metals is one because they belong to group 1 and after losing one electron, they get noble gas configuration.
• Valency of group 18 elements is zero because they are noble gases have fully filled valence shell. Therefore, they don't participate in gain or lose any electron.
• When we move from left to right in a period, the valency increase up to group 14 i.e. carbon family after that valency decreases to zero.