Iodine forms `I_(3)^(-)` but `F_(2)` does not form `F_(3)^(-)` ions. Why ?

Explanation

To understand why iodine forms the ion \( I_3^- \) while fluorine does not form \( F_3^- \), we need to analyze the electronic configuration and bonding characteristics of both elements.

### Step 1: Understanding the Formation of \( I_3^- \)

Iodine (\( I \)) has an atomic number of 53 and its electronic configuration is \( [Kr] 4d^{10} 5s^2 5p^5 \). This means that iodine has 7 valence electrons (2 from \( 5s \) and 5 from \( 5p \)).

When iodine forms the \( I_3^- \) ion, it involves three iodine atoms. The structure of \( I_3^- \) can be represented as follows:

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