Periodic Table · element

Protactinium

Pa · Z 91

atomic number

91

atomic mass

231.04

notation

Pa

group

f-block: Actinide

period

7

state0c

Solid

state20c

Solid

occurrence

From Decay

density

15.37

melting pt

1570

boiling pt

4027

discovered

1913

abundance

1.4e-06

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From the All Periodical Elements database in Notion, last edited 2026-08-15. This page is the row, rendered by the build; nothing on it is written by hand.