# Chapter 8 - Sections 8.1-8.9 - Exercises - Problems by Topic: 65d

$[Ar]4s^{2}3d^{7}$ $[Ar]3d^{6}$

#### Work Step by Step

Write the electron configuration for an uncharged Co atom. Three electrons must be removed from Co to form the ion $Co^{3+}$.Remove these electrons to its energy level and change the corresponding electron configuration.

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