Here's how to determine the electron configuration of In³⁺:

1. Neutral Indium (In)

* Indium has an atomic number of 49, meaning it has 49 electrons.

* Its electron configuration is: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p¹

2. Indium (III) Ion (In³⁺)

* Indium loses 3 electrons to form the In³⁺ ion.

* The three electrons lost come from the highest energy levels (5s² and 5p¹)

3. Electron Configuration of In³⁺

* The final electron configuration of In³⁺ is: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 4d¹⁰