Valency

Valency, in chemistry, refers to the measure of the capacity of an atom to combine with other atoms. It is determined by the number of chemical bonds an atom can form.

Here are a few key aspects of valency:

• Combining Capacity: It represents the number of hydrogen atoms or other univalent atoms (atoms that form only one bond) that an atom can combine with.
• Determined by Electrons: Valency is related to the number of electrons in the outermost shell (valence shell) of an atom. Atoms tend to gain, lose, or share electrons to achieve a stable electron configuration, typically with eight electrons in their valence shell (octet rule).
• Variable Valency: Some elements can exhibit variable valency, meaning they can form different numbers of bonds depending on the chemical environment. Transition metals are particularly known for this.
• Examples:
  • Hydrogen (H) has a valency of 1.
  • Oxygen (O) has a valency of 2.
  • Nitrogen (N) often has a valency of 3.
  • Carbon (C) typically has a valency of 4.

For more detailed information, you can refer to these resources:

• Britannica - Valency
• LibreTexts - Valence Bond Theory