Answer: The valency of oxygen, O2 is 2 because Oxygen needs 2 electrons to fill its outer valence shell to achieve stability like noble gases.
Valency is a concept in chemistry that indicates the combining capacity or the number of electrons an element can gain, lose, or share to form chemical bonds with other elements.
Here’s why oxygen has a valency of 2:
- Electron Configuration: Oxygen has an electron configuration of 1s² 2s² 2p⁴. In its outermost electron shell (second shell), it has six electrons.
- Octet Rule: Oxygen, like other elements, tends to achieve a stable electron configuration by filling its outermost shell with eight electrons (known as the octet rule). To do this, it needs to gain or share two electrons.
- Formation of Covalent Bonds: In most of its compounds, oxygen forms covalent bonds by sharing electrons with other elements. Each oxygen atom shares two electrons with another atom, resulting in a double bond, and fulfilling the octet rule.
So, the valency of oxygen is 2 because it can form two covalent bonds by sharing two electrons with other atoms, allowing it to attain a stable electron configuration. This property makes oxygen a key component in numerous molecules and compounds in chemistry and biology.