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.
Best Answer
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.