Valency refers to an element's combining power when forming compounds, and is determined by the number of electrons in the outer shell. Elements in the same group of the periodic table share the same valency, as shown in the valency table where group number corresponds to valency. Valency was developed in the 19th century to explain molecular structures of inorganic and organic compounds.

1. CHEMISTRY
VALENCY
BY
G.BRAGADEESWAR

2. WHAT IS VALENCY ?
 Valency of an element is a measure of its combining power with other atoms when it forms chemical
compounds or molecules.
 Elements in the same group of the periodic table have the same valency.
 The valency of an element is related to how many electrons are in the outer shell.
 The concept of valence was developed in the second half of the 19th century and was successful in
explaining the molecular structure of inorganic and organic compounds.

3. VALENCY TABLE
Group
number
1 2 3 4 5 6 7 8
Valency 1 2 3 4 3 2 1 0
 The noble gases have the valency 0 as they do not usually combine with other elements.