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Periodic Table

The elements with IUPAC/CIAAW standard atomic weights — browse by position or list.

Selected element

Element
Zirconium
Atomic number
40
Standard atomic weight
91.222
Period
5
Group
4
Groups 1–2 Groups 3–12 Groups 13–18 Lanthanoids (57–71) & actinoids (89–103), shown outside the 18 groups

Scroll the table horizontally to view all 18 groups.

Standard atomic weights: IUPAC/CIAAW abridged standard atomic weights, 2024 table (elements shown with “–”/“Not assigned” have no standard atomic weight). Layout — periods and groups 1–18 — follows the IUPAC periodic-table convention; lanthanoids (57–71) and actinoids (89–103) are shown outside the 18 groups. Need a formula weight? Use the Molecular Weight Calculator.

Element list