Which of the following chemical equations correctly represents the third ionization of aluminum?

• A. Al^{+} ightarrow Al^{2+} + e^{-}
• B. Al ightarrow Al^{3+} + 3e^{-}
• C. Al^{3+} ightarrow Al^{4+} + e^{-}
• D. Al^{2+} ightarrow Al^{3+} + e^{-}

Answer: (D)

Verified step by step guidance

1. Understand what ionization means: Ionization is the process of removing electrons from an atom or ion, resulting in a positively charged ion.
2. Identify the order of ionizations for aluminum (Al): The first ionization removes one electron from neutral Al to form Al^{+}, the second ionization removes another electron from Al^{+} to form Al^{2+}, and the third ionization removes an electron from Al^{2+} to form Al^{3+}.
3. Write the general form of the third ionization reaction: It involves removing one electron from the Al^{2+} ion, so the equation should be Al^{2+} \rightarrow Al^{3+} + e^{-}.
4. Check the given options against this understanding: The correct third ionization must start with Al^{2+} and produce Al^{3+} plus an electron.
5. Confirm that the other options do not represent the third ionization: For example, Al \rightarrow Al^{3+} + 3e^{-} represents the removal of three electrons at once (not stepwise), and Al^{3+} \rightarrow Al^{4+} + e^{-} is not typical for aluminum as it rarely forms a +4 ion.