What is the Valency of MgO?

The valency of both Magnesium (Mg) and Oxygen (O) in Magnesium Oxide (MgO) is 2.

Here's why:

Magnesium (Mg) has 2 valence electrons (electrons in its outermost shell). To achieve a stable electron configuration (like that of a noble gas), it tends to lose these 2 electrons, forming a Mg²⁺ ion.

Oxygen (O) has 6 valence electrons. To achieve a stable electron configuration, it tends to gain 2 electrons, forming an O^2- ion.

In MgO, Magnesium donates its 2 valence electrons to Oxygen. This results in an ionic bond between Mg²⁺ and O^2- ions. Since Magnesium loses two electrons and Oxygen gains two electrons, their valencies are both 2. The charges effectively cancel each other out, resulting in a neutral MgO molecule.

In summary:

• Magnesium (Mg): Valency = 2 (tends to lose 2 electrons)
• Oxygen (O): Valency = 2 (tends to gain 2 electrons)