Difference between revisions
periodic-table
Status and infobox
- status:
—→ solved - tier:
—→ V3 - kind:
—→ problem - year:
—→ 1817 - statement:
—→ Is there an organizing principle behind the chemical elements?
Source +20 −0
+---
+title: The order of the elements
+kind: problem
+status: solved
+tier: V3
+year: 1817
+statement: Is there an organizing principle behind the chemical elements?
+space: materials
+---
+Mendeleev left gaps for elements not yet found and predicted their properties; gallium, scandium and germanium filled them within 17 years. Moseley's X-ray measurements showed the order was nuclear charge, not weight. Quantum mechanics later explained why the pattern exists.
+
+*Evidence tier V3 is the import default for a result the curation records as settled in the published record. No formal proof or certificate is attached to this page yet.*
+
+Closed 1869, Dmitri Mendeleev; 1913, Henry Moseley ties order to atomic number.
+
+## Sources
+
+- [Wikipedia: Periodic table](https://en.wikipedia.org/wiki/Periodic_table)
+
+[[Space:materials|Materials]] · [[Continent:chemistry|Chemistry and matter]]
Revision 132 as rendered
Mendeleev left gaps for elements not yet found and predicted their properties; gallium, scandium and germanium filled them within 17 years. Moseley's X-ray measurements showed the order was nuclear charge, not weight. Quantum mechanics later explained why the pattern exists.
Evidence tier V3 is the import default for a result the curation records as settled in the published record. No formal proof or certificate is attached to this page yet.
Closed 1869, Dmitri Mendeleev; 1913, Henry Moseley ties order to atomic number.