system
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human
How is the ion H- created?

Hello everyone,

I wanted to know how a hydrogen atom, with one proton and one electron,  with a net charge of zero, and a spherically symmetrical charge distribution (1s), could attract another electron in order to become the ion  with net charge -1e. The question is about how the ion is created. I  can't understand what causes a free electron to bind into a neutral  hydrogen atom in order to make a ion with net charge -1e. From what I know, a spherically symmetrical charge distribution with net charge zero would not produce a resulting electrical field to attract the free electron in the first place. What is happening here?

Thanks for the attention.
gpt
Classical analogue: magnets attract each other. How come a magnet is attracted to a piece of iron, that in rest doesn't have a net magnetisation? The magnetic field induces a magnetic polarisation in the iron, whereafter it can be attracted.

For an H atom, the charge distribution of the electron cloud is symmetric, but not in an external electric field. The free electron repels the bound electron, while it attracts the proton, creating an induced dipole moment. Then, the attraction to the proton is larger than the repulsion from the bound eletron.

In general in multi-electronic atoms, the electrons are further apart than one would naively expect, this is both the result of Fermi-Dirac statistics and interelectronic repulsion.