Final answer:
The complete electron configuration of I- is [Kr]4d10 5s2 5p6, which is similar to Xe, while the configuration for Ca2+ is [Ar], identical to the electron configuration of the noble gas argon (Ar).
Step-by-step explanation:
Writing the complete electron configuration for ions requires understanding how electrons are added or removed from the neutral atom's configuration. Let's take the ions I− and Ca2+ as examples.
I− (Iodine ion) - Neutral iodine has 53 electrons, and its electron configuration is [Kr]4d105s25p5. Since the iodide ion has gained one electron, its configuration becomes [Kr]4d105s25p6, which is the same as the electron configuration for xenon (Xe).
Ca2+ (Calcium ion) - Neutral calcium has 20 electrons with the configuration [Ar]4s2. When it forms a cation by losing two electrons, the Ca2+ ion has the electron configuration [Ar], which is the same as the noble gas argon (Ar).