Which of the following ions is isoelectronic with the oxide anion O^{2-}?

• A. N^{3-}
• B. F^{-}
• C. Cl^{-}
• D. Na^{+}

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the term 'isoelectronic.' Isoelectronic species have the same number of electrons, regardless of their element or charge.
2. Step 2: Determine the number of electrons in the oxide anion \(O^{2-}\). Oxygen has an atomic number of 8, so neutral oxygen has 8 electrons. The \$2-\( charge means it has gained 2 extra electrons, totaling \)8 + 2 = 10$ electrons.
3. Step 3: Calculate the number of electrons for each ion given in the options:
4. - \(N^{3-}\): Nitrogen has 7 electrons, plus 3 extra electrons from the charge, total \$7 + 3 = 10$ electrons.
5. - \(F^{-}\): Fluorine has 9 electrons, plus 1 extra electron from the charge, total \$9 + 1 = 10$ electrons.
6. - \(Cl^{-}\): Chlorine has 17 electrons, plus 1 extra electron, total \$17 + 1 = 18$ electrons.
7. - \(Na^{+}\): Sodium has 11 electrons, minus 1 electron due to positive charge, total \$11 - 1 = 10$ electrons.
8. Step 4: Compare the total electrons of each ion to the oxide anion's 10 electrons to identify which ions are isoelectronic with \(O^{2-}\).
9. Step 5: Conclude which ion(s) share the same electron count as \(O^{2-}\), confirming the correct answer.