Question #2b6ab

1 Answer
Feb 6, 2018

It comes down to the fact that cesium requires the least amount of energy to remove its valence electron - a key part of the reaction.

Explanation:

The reaction between alkali metals and halogens involves the transfer of an electron from metal to non-metal. While this is not the largest contributor to the total energy effect seen for the reaction, it is a significant one.

Cesium has the lowest ionization energy of the alkali metals. That means it has the valence electron that requires the least amount of energy to remove. This contributes to making the overall energy change for the reaction a large negative value, which favours the occurrence of the reaction.