How many electrons are present in the oxide ion, O^{2-}?

• A. 8
• B. 10
• C. 10
• D. 18

Answer: (C)

Verified step by step guidance

1. Identify the atomic number of oxygen, which tells you the number of protons in a neutral oxygen atom. For oxygen, the atomic number is 8, so a neutral oxygen atom has 8 electrons.
2. Understand that the oxide ion, O^{2-}, has gained 2 extra electrons compared to the neutral oxygen atom because of the 2- charge.
3. Calculate the total number of electrons in the oxide ion by adding the 2 extra electrons to the 8 electrons of the neutral oxygen atom.
4. Write the expression for the total electrons in the oxide ion as: \$8 + 2$.
5. Conclude that the oxide ion, O^{2-}, has 10 electrons in total.