# Can an electron escape an atom?

**URL:** <https://boards.straightdope.com/t/can-an-electron-escape-an-atom/43015>\
**Category:** Factual Questions\
**Created:** [November 28, 2000, 1:01pm UTC](https://boards.straightdope.com/t/can-an-electron-escape-an-atom/43015 "2000-11-28T13:01:07Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![KV](https://avatars.discourse-cdn.com/v4/letter/k/8baadc/32.png) [@KV](https://boards.straightdope.com/u/KV)\
**Post date:** [November 28, 2000, 1:01pm UTC](https://boards.straightdope.com/t/can-an-electron-escape-an-atom/43015/1 "2000-11-28T13:01:07Z")

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can an electron gain enough energy to escape the atom?  
Also, are the number of particles in a mole a constant?

I’m confused ☹

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**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\
**Post date:** [November 28, 2000, 1:05pm UTC](https://boards.straightdope.com/t/can-an-electron-escape-an-atom/43015/2 "2000-11-28T13:05:56Z")

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Yes, electrons can gain enough energy to escape an atom. Many years ago I worked with folks who excited atoms with a single electron above the “filled” shells to very high energy levels. These so=called “Rydberg” atomes had a reputation for being “floppy” and delicate – it was easy for them to pick up thermal energy and self-ionize.

The number of atoms in a mole IS constant.

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**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\
**Post date:** [November 28, 2000, 1:10pm UTC](https://boards.straightdope.com/t/can-an-electron-escape-an-atom/43015/3 "2000-11-28T13:10:44Z")

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Electrons escaping from an atom? Sure, happens all the time. For example, an x-ray photon striking the atom can transfer enough energy to the atom forthe atom to emit an electron. An atom with one (or more) electorn short is charged positively - it’s a positive ion. Hence the term “ionizing radiation” which applies to X-rays, gamma rays, etc.

Also, if you dissolve some type of salt in water, the atoms come apart and become ions - some have an extra electron, some are missing an electron.

A “mole” is a dimensionless unit - i.e. it’s just a number, like “gross” or “dozen.” So the number of atoms in a mole is by definition constant. Just like the number of roses in a dozen is always constant (12).

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**Author:** ![KV](https://avatars.discourse-cdn.com/v4/letter/k/8baadc/32.png) [@KV](https://boards.straightdope.com/u/KV)\
**Post date:** [November 29, 2000, 12:50pm UTC](https://boards.straightdope.com/t/can-an-electron-escape-an-atom/43015/4 "2000-11-29T12:50:24Z")

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thanks, I was confused… but no longer

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**Author:** ![Astroboy14](https://avatars.discourse-cdn.com/v4/letter/a/df705f/32.png) [@Astroboy14](https://boards.straightdope.com/u/Astroboy14)\
**Post date:** [November 29, 2000, 1:10pm UTC](https://boards.straightdope.com/t/can-an-electron-escape-an-atom/43015/5 "2000-11-29T13:10:11Z")

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An electron _ **CAN** _ escape an atom… _if_ it has an accomplice on the outside willing to sneak in a key in a cake, or crash through the wall at an appropriate time in a truck…

The salient question here is: how long can it remain at large before the Atomic Guard catches up to it?