Elemental Chemistry

Here, we will explain chemistry in terms of elements and molecules.

Class of Elements

The following schema organizes elemental atoms and molecules:

ratni1: atoms
ratni2: atomic numbers (number of protons)
ratni3: mass numbers (number of nucleons)

rakle1: atomic numbers (number of protons)
rakle2: groups
rakle3: periods (number of full electron shells)

groups1: atoms
groups2: ???

xukmi1: physical objects
xukmi2: molecules
xukmi3: purities (0, 1]

Note that ratni3 is always at least ratni2.

Note that {rakle} has two more places which we are ignoring; rakle4 is a shadow of rakle2, and rakle5 is fixed by the Standard Model.

Groups should probably be indexed by natural numbers. Currently, there are experimental lujvo for individual elements within a group, but those would only be useful as indirect labels.

Note that membership in {xukmi} is inherently fuzzy, with xukmi3 as the fuzziness. Also note that 100% purity is physically unlikely but legal for textbook examples.

One open question is how atoms form molecules. Something with the structure:

x1 (molecule) has underlying graph x2 (graph) where x3 (atom) is assigned to vertex x4

For now, we suggest a sharp barrier between atoms and molecules.

One open question is whether molecules in dynamic equilibrium are always present, probabalistically present, or conditionally present; we assume the former. For example, in the equilibrium reaction for water:

2 H₂O <=> H₃O⁺ + HO⁻

Do we say that DI water is 100% H₂O? 50% HO⁻? Does it have more exotic species? Perhaps it depends on laboratory conditions. In this particular case, there is a solid argument that water is H₂O by default, because it only self-ionizes about once per 10 hours (per pair of molecules) and self-neutralizes about 1 picosecond later, yielding an average purity of 15-16 nines.

Molecule gismu are extensionally identified with sets of physical objects composed of those molecules. This includes gismu which cover multiple molecules, as noted below.

Note that the logic of chemical reactions, stoichiometry, is a linear logic which is not generated from the posetal logic of Selb or the deductive logic of Loj. Instead, given any family of stoichiometric equations which holds parametrically over a relation of elements, Selb has a posetal logic generated by its subrelations. For example, all halogens have hydrogen halides; for halogen x, there are environmental conditions where the stoichiometric equation holds:

H₂ + x₂ => 2 Hx

The corresponding posetal logic is generated by subrelations of {kliru}.

Groups of Chemical Elements

These gismu refer to entire columns of the periodic table.

sodna: group 1, sodas, alkali metals; lithium, sodium, potassium, rubidium, caesium, francium
kliru: halogens; fluorine, chlorine, bromine, iodine, astatine, tennessine
navni: noble gasses; helium, neon, argon, krypton, xenon, radon, oganesson

Hydrogen should also get {cidro}, perhaps? It ought to get its own group, as too many stoichiometric families of group 1 metals exclude it.