The electron configuration of Fe^{2+} is [Ar] 3d^6. Which of the following is true about Fe^{2+}?

• A. Fe^{2+} has the same number of electrons as neutral Fe.
• B. Fe^{2+} has an electron configuration of [Ar] 3d^4.
• C. Fe^{2+} has gained two electrons compared to neutral Fe.
• D. Fe^{2+} has lost two electrons compared to neutral Fe.

Answer: (D)

Verified step by step guidance

1. Recall that the neutral iron (Fe) atom has an atomic number of 26, meaning it has 26 electrons in its neutral state.
2. Understand that the electron configuration of neutral Fe is [Ar] 3d^6 4s^2, where [Ar] represents the electron configuration of argon (18 electrons).
3. Recognize that Fe^{2+} means the iron ion has lost 2 electrons compared to the neutral atom, so the total number of electrons in Fe^{2+} is 26 - 2 = 24 electrons.
4. Determine the electron configuration of Fe^{2+} by removing the two electrons from the highest energy level orbitals first, which are the 4s electrons, resulting in [Ar] 3d^6.
5. Compare the statements given: since Fe^{2+} has fewer electrons than neutral Fe, it has lost two electrons, not gained them, and its electron configuration is correctly given as [Ar] 3d^6.