# Which Has The Maximum Value of Electron Affinity?

By BYJU'S Exam Prep

Updated on: September 13th, 2023

The amount of energy emitted when an electron is added to the outer orbit of an isolated gaseous atom of an element while at the ground level is called the electron affinity (more specifically, the first electron affinity) of the fraction of that element. Chlorine has the maximum Electron affinity among all the Periodic Table elements.

Table of content

## What is An Electron Affinity?

The energy emitted by inserting one-mole electron into one mole gaseous atom of an element to turn it into a negative ion is called the electron affinity of that element. The electron affinity is the energy required to enter a new electron in the last orbit of a part. If more power is needed, electron affinity will be more, and electron affinity will be less if less energy is required.

Electron Affinity is a Periodic Property

If the atomic radius of an element is large, then the electron’s attraction in the last orbit by the nucleus is less. Therefore, it is straightforward to enter the electron. That is, the electron affinity is less. Again, if the atomic radius of that element is small, then the electron’s attraction in the last orbit by the nucleus is more. Therefore, it is not possible to insert electrons easily. That is, the electron affinity is more.

In the periodic table, the atomic radius decreases when we move from the left to the right. Then the value of electron affinity increases. Again, the atomic radius increases from top to bottom of the same group. That is, electron affinity is diminished.

Electron affinity in the Halogen group

Going from the top to the bottom of a group of periodic tables, the combined effect of the increase in the atomic size and the shielding effect decreases the effective nuclear charge. As a result, electron affinity decreases.

However, the order of electron addition of halogen elements—Cl>F>Br>I. The electron addiction to fluorine is unexpectedly low compared to chlorine. In the following table, you will find the Electron affinity of Halogen elements.

 Element Name Electron Affinity F -328.8 kj mol-1 Cl -348.8 kj mol-1 Br -324 kj mol-1 I -295 kj mol-1

So, chlorine has the highest Electron affinity among all the Periodic Table elements.

Summary

## Which Has The Maximum Value of Electron Affinity?

In the periodic table group, the elements’ electron affinity is usually reduced from top to bottom. However, there are exceptions to this order. If we look at the order of electron affinity in the halogen group, we will notice that the order of electron affinity is Cl>F>Br>I. The electron affinity to fluorine is unexpectedly low compared to chlorine.

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