Question

When the elements copper (Cu) and oxygen (O) chemically combine, they form...​

Answer 1

REACTION OF COPPER -

• Copper is a metal with common valency +1 and +2.
• Copper reacts with atmospheric moisture and leads to corrosion of the metal.
• Copper on reaction with oxygen to form copper (II) oxide, a red layer. $Cu_2O$
• Later, Copper (I) oxide reacts with atmospheric oxygen to form copper(I) oxide, a black layer. (CuO)
• Corrosion of copper is a slow process because of the formation of the oxide layer.
• The aqueous solution of Copper (I) is colorless whereas copper (II) is blue in color.