I think you could do a periodic table of html elements, but the author hasn't done it here - at least not the "periodic" part.
For instance, I'd expect "head" and "body" to be in one period, and "thead" and "tbody" in the same groups of a different period. That could put "table" in the same group as "html", with them both being "container" periods. (with "iframe" being in the same group as "html"/"table"?) "fieldset" looks like it should fit in there somewhere also, possibly with "legend" being an equivalent to "title".
Then you'd have periods like "block elements" and "inline elements", with e.g. "blockquote" and "q" being in the same group for each. Ditto "div" and "span" - which I think should be in the same group ("overly generic elements"?), not in the same period as the author has them.
Similarly, "dl", "ul" and "ol" are 3 list periods, with "dd", "li" and ... "li" in the next group - where "li" being a repeated element is an interesting bit of information you could extract from such a table.
Note that I missed "dt" in the list elements periods above, but then there's a similarity between the "dl", "dt", "dd" period, and a possible "tr", "th", "td" period.