Ionizing radiation, as I've learnt it, ionizes an atom by supplying enough energy to essentially "knock" an electron off the atom — that is, by exciting the electron to a level that is gets freed from the atom it was previously bound to. However, I had this belief contested by a Youtube video, whose host said that:

[...] (the argon) atom can be made negatively charged by having an electron put on it [...]

How does that work? How can radiation negatively ionize an atom, not through the removal of a proton (like is discussed in this thread) but rather by the addition of an extra electron (or more)?

The entire context here is about ionizing radiation and how it could ionize an atom (in this case, Argon) negatively so an answer explaining that would be perfect.

  • $\begingroup$ The knocked-off electron should go somewhere. That somewhere is the other atom that'll get negatively charged. $\endgroup$
    – Ruslan
    Sep 24, 2021 at 12:34
  • $\begingroup$ Is the YouTube video you mentioned specifically talking about ionizing radiation? Or just ionization in general? A link would be helpful. $\endgroup$ Sep 24, 2021 at 12:47
  • $\begingroup$ It's talking about ionizing radiation in particular. $\endgroup$
    – Shane
    Sep 24, 2021 at 12:55

1 Answer 1


Confusion here between ionizing radiation and ionization/ions in general.

Ions are atoms that lack electrosn or have some extra ones, which makes them positively/negatively charged.

Ionizing radiation kicks an electron (or more) from an atom, producing a positively charged ion.

Ionization can be achieved by different means, not necessarily via radiation. E.g., a $NaCl$ salt dissolved in water will separate into ions: $$ NaCl \leftrightarrow Na^{+}+Cl^{-} $$

In a gas ions can arise from atoms capturing electrons, e.g., if these electrons were previously released by other atoms as a result of ionizing radiation. In gas discharge tubes the ions may also arise from the electron flow, atomic collisions, or molecules torn apart by electric field.

  • $\begingroup$ @MichaelSeifert a typo, thanks. $\endgroup$ Sep 24, 2021 at 12:46

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.