What is the oxidation state of copper (Cu) in Cu_2O?

• A. +1
• B. -1
• C. 0
• D. +2

Answer: (A)

Verified step by step guidance

1. Identify the chemical formula given: Cu_2O, which consists of copper (Cu) and oxygen (O).
2. Recall that oxygen almost always has an oxidation state of -2 in compounds (except in peroxides or when bonded to fluorine).
3. Let the oxidation state of copper be x. Since there are 2 copper atoms, their total contribution to charge is 2x.
4. Write the equation for the sum of oxidation states in the compound, which must equal zero because Cu_2O is neutral: 2x + (-2) = 0.
5. Solve the equation for x to find the oxidation state of copper: 2x - 2 = 0, so 2x = 2, and therefore x = +1.