Periodic table / Protactinium

Overview

Protactinium is a chemical element with symbol Pa and atomic number 91. It is a dense, silvery-gray metal which readily reacts with oxygen, water vapor and inorganic acids. It forms various chemical compounds where protactinium is usually present in the oxidation state +5, but can also assume +4 and even +2 or +3 states.

Electron configuration

The electron configuration of Protactinium is [Rn] 5f2 6d1 7s2, with electron shells of 2, 8, 18, 32, 20, 9, 2.

Physical and chemical properties

Protactinium is classified as a actinide. It has an atomic mass of 231.036 and exists as a solid at standard conditions, appearing as bright, silvery metallic luster.

Real-world uses of Protactinium

Protactinium is an actinide studied primarily in nuclear science and research due to its radioactive properties.

Interesting facts about Protactinium

• Protactinium has the atomic number 91 and chemical symbol Pa.
• It belongs to period 7, group 3 of the periodic table.
• Protactinium was discovered by William Crookes.

Explore Protactinium interactively

Want to compare Protactinium with other elements or see it highlighted on the full table? Open the interactive periodic table and click on Pa to explore properties, trends, and neighboring elements. You can also test your knowledge with our periodic table quiz game.