Layouts
Three arrangements of the same 118 elements. Nothing is added or removed between them — a layout is a set of positions, not a set of elements.
ShowingBlock
- s-block
- p-block
- d-block
- f-block
These four colours are the shape of the table. A block is as wide as its subshell is deep — s holds 2 electrons, p holds 6, d holds 10, f holds 14 — so the blocks are 2, 6, 10 and 14 columns across. Count them. The outline of the table is that and nothing else.
not known — hatched on every lens — never a colour, never a position on the scale
no published value exists for this element
Standard. The familiar form, with the f-block lifted out into two footnote rows to keep the page a manageable width. That footnote is a printing decision, not a chemical one.
Left-step, after Charles Janet (1928). Rows end on a completed s subshell, so each row is exactly one turn of the filling rule. The blocks run f, d, p, s from the left, and the shape of the rule is much harder to miss than it is in the standard form.
Spiral, after Theodor Benfey (1964). One continuous run from hydrogen to oganesson, each period a full turn. It gives up the tidy columns to keep the sequence unbroken.
They disagree about presentation and agree about chemistry. That is worth noticing: the standard table is how the field settled on organising the facts, not a fact itself.