Protactinium (Pa), element 91 – Learn Acer periodic table

Actinide, atomic number 91.

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.

Symbol Pa. Atomic mass 231.035882 u. Group 3, period 7. Electron configuration [Rn] 5f2 6d1 7s2. Electrons per shell 2, 8, 18, 32, 20, 9, 2. State at room temperature: Solid. Melting point 1567.8 °C, boiling point 4026.8 °C. Discovered by William Crookes.

Element data from Wikipedia, CC BY-SA 3.0.

Protactinium (Pa), element 91 – Learn Acer periodic table

Protactinium

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