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CBSE - X - Chemistry - Periodic Classification of Elements

Please explain to me the reason why valency across a period first increases and then decreases

Asked by joshiraghavendra53 27th February 2015, 1:40 PM
Answered by Expert

Answer:

As we move from left to right in a period, the number of valence electrons in electrons increases from 1 to 8. The elements in a period have consecutive atomic numbers.

Valency is the number of electrons present in the outermost shell of an orbital.

On moving from left to right in each period, the valency increases from 1 to 4 and then decreases to zero.

Third period

Na

Mg

Al

Si

P

S

Cl

Ar

Valency

1

2

3

4

3

2

1

0

 

Answered by Expert 1st March 2015, 11:55 AM

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