Thorium-229

Thorium-229 has an atomic mass of 229u. It contains 90 protons, 90 electrons, and 139 neutrons. Its atomic weight is 229.03176243 and has no abundance. On the periodic table it is located under the group actinides, period 7, block f. It is a solid at room temperature. Thorium is a naturally-radioactive metal found at very low levels in soil, rocks, and water. All of its isotopes are radioactive, whether they are natural or man-made.

 

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