Question

less energy is released in adding an electron to iodine than to chlorine because the radius of iodine is larger and the electron is added at a distance further from the nucleus.

Answer 1

Less energy is released when adding an electron to iodine than to chlorine due to iodine's larger atomic radius, resulting in reduced nuclear attraction and a lower electron affinity.

Step-by-step explanation:

The question asks us to understand why less energy is released when adding an electron to iodine than to chlorine. This phenomenon is explained by the concept of electron affinity and atomic radius. Electron affinity refers to the change in energy when an electron is added to a neutral atom, forming an anion. As the atomic radius increases, which it does as we move down a group in the periodic table, the outermost electrons are further from the nucleus. Consequently, there is decreased nuclear attraction on the added electrons because of this greater distance and increased electron-electron repulsion as the electron cloud expands.

For instance, the iodine atom has a much larger radius than the chlorine atom, as it is found further down group 17 of the periodic table. This larger distance from the nucleus to the valence shell results in iodine having a lower electron affinity than chlorine. Therefore, adding an electron to iodine releases less energy compared to adding one to chlorine.