[Hasclepio]

Hi all!

I know the definition of electron affinity (energy)  and i know how it varies across the periodic table but do not understand why a higher affinity implies that electrons tend to capture, what is the reason?

Thank you very much

[Dan]

What is the formal definition of electron affinity?

[Hasclepio]

What is the formal definition of electron affinity?

The electron affinity of an atom or molecule is defined as the amount of energy released when an electron is added to a neutral atom or molecule to form a negative ion.

But I already know the definition. I have doubts about a qualitative idea derived from that definition: why a negative energy (affinity) means that the atom attracts other electrons with more "force" than another atom with less affinity?

[Dan]

Things happen because they are energetically favourable (i.e. energy is released). If you measure how energetically favourable something is, you have measured how easily it happens. The more energetically favourable it is, the more easily it happens.

[Hasclepio]

Things happen because they are energetically favourable (i.e. energy is released). If you measure how energetically favourable something is, you have measured how easily it happens. The more energetically favourable it is, the more easily it happens.

And what are the physical laws that support your writing? Entropy and thermodynamics?

thank you very much

[Dan]

Yes, this is thermodynamics (of which entropy is a part).