1. Copper (Cu): Copper can form two common ions: Cu⁺ and Cu²⁺. This is because it can lose one electron from its 4s orbital or two electrons from both the 4s and 3d orbitals.
2. Iron (Fe): Iron can form two common ions: Fe²⁺ and Fe³⁺. This is because it can lose two electrons from its 4s orbital or three electrons from both the 4s and 3d orbitals.
These metals exhibit variable valency, meaning they can form ions with different charges depending on the specific chemical environment.
