# Why is chlorine more reactive than iodine?

Nov 8, 2016

Chlorine has a higher effective nuclear charge, and therefore should be more oxidizing than iodine.

#### Explanation:

The nuclear charge of chlorine is less shielded by intervening electrons. Thus chlorine gas should be a better oxidant.

If we turn to reduction potentials, which we should do as scientists because scientists must utilize quantitative data, we find:

$\frac{1}{2} C {l}_{2} + {e}^{-} \rightarrow C {l}^{-}$ ${E}^{\circ} = 1.36$

$\frac{1}{2} {I}_{2} + {e}^{-} \rightarrow {I}^{-}$ ${E}^{\circ} = 0.54$

How is this consistent with the given proposition?