I was wrong. In re-reading my own source:
"The dividing line between ionizing and non-ionizing radiation in the electromagnetic spectrum falls in the ultraviolet portion of the spectrum. It is therefore useful to divide the UV spectrum into two categories: UVA and UVB. Radiation at the high-energy end of the UV spectrum can be as dangerous as x-rays or -rays."
Yes it's interesting. The Wiki article here: https://en.wikipedia...iki/Ultraviolet indeed claims that UV is "non-ionising", but then it gives, lower down, a table of photon energy ranges, in eV, for near, middle and far UV.
The 1st ionisation energy of sodium, which admittedly is an alkali metal and thus is one of the most easily ionised elements, is about 5eV. This is well within the middle UV range. There is a table of these ionisation energies here: https://en.wikipedia...nization_energy
This shows that while most are of course higher than for the alkali metals, in many cases they are still arguably within the upper end of the UV ranges as defined in the Wiki energy table.
I have the impression that perhaps the standard use of the term "ionising radiation" has in mind the effect on body tissues, i.e. the risk of damage from exposure, and that what people often really mean- without perhaps realising it - is radiation that can ionise the main elements found biochemistry: C, N, O, H. All of these, you will notice, are above 10eV - double that of sodium.
(Note for other readers: accounting for the periodicity of the 1st ionisation energy is one of the classic successes of atomic quantum theory and is something every 6th form chemist learns!)
Edited by exchemist, 08 April 2017 - 10:24 AM.