Order of Electron Gain Enthalpy in Halogens
- The correct order of amount of energy released in electron gain enthalpy among halogens is as follows:
1. Fluorine
2. Chlorine
3. Bromine
4. Iodine

Reasoning
- The trend in electron gain enthalpy across the halogens can be explained by the increase in atomic size as we move down the group.
- Fluorine has the highest electron gain enthalpy due to its small atomic size, strong nuclear charge, and stable electronic configuration. When an electron is added to a fluorine atom, it experiences a strong attractive force from the nucleus.
- As we move down the group, the atomic size increases, leading to a decrease in electron gain enthalpy. Chlorine has a lower electron gain enthalpy compared to fluorine due to its larger atomic size.
- Bromine, with an even larger atomic size, has a lower electron gain enthalpy than chlorine. The trend continues with iodine having the lowest electron gain enthalpy among the halogens due to its large atomic size and weak nuclear charge.
In summary, the order of electron gain enthalpy in halogens is determined by the atomic size and nuclear charge of the elements, with smaller atoms having higher electron gain enthalpy values.

I>Br>F>Cl......For know full explanation inbox me