Question

6. What is meant by valency? Write the valency of Na, Mg, Ca and Al.​

Answer 1

Answer:

the combining capacity of an atom for another element is known as valency.

na=1

mg=2

ca=2

al=3

Answer 2

Answer: The number of electrons that are shared, lost or gained by an atom during a chemical reaction is called as the valency of the element.

Explanation:

Eg. - Sodium Chloride

[Sodium electrons = 11 $(2,8,1)$      Chlorine electrons = 17 $(2,8,7)$]

= By electronic configuration,

Sodium Shares or Loses Electron to Chlorine which Gains Electron

No. of atoms lost by Na = 1

No. of atoms gained by Cl = 1

Why only 1?

Because, if 1 electron is shared to Cl by Na

its electronic configuration would become $(2, 8, 1 - 1)$ 2, 8

Plus, the electronic configuration of Cl will become $(2, 8, 7 + 1)$  2, 8, 8

Got it?

Hope so, yes