The periodic table
All 118 elements, each with its own page. Masses and radii are read from the same table the chemistry engine parses structures with, so a weight quoted here and a weight used in a calculation cannot disagree.
- s-block
- p-block
- d-block
- f-block
What this table does and does not assert
Standard atomic weights and the two radii come from the chemistry engine's own periodic table. Group, period, block and category are derived from the atomic number by rules that are written down and tested rather than transcribed, which is why they are the same on every page here.
The f-block elements carry no group number. Whether lanthanum or lutetium belongs in group 3 is genuinely unsettled, and printing one of them would be asserting a fact that is not settled. Electron configurations are filled in the aufbau order and written in the conventional (n, ℓ) order — iron is [Ar] 3d6 4s2, not [Ar] 4s2 3d6. Twenty elements have a ground state that departs from aufbau, and those carry the documented configuration and say so.
Melting points, boiling points and densities are deliberately absent. They are the numbers most often copied around the web with their conditions or units quietly mangled, and we do not have a source for them we would be willing to name on the page.