#89
Ac
Actinium
227 u

Actinium

Actinide
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Properties

Symbol Ac
Atomic Number 89
Atomic Mass 227
Protons 89
Neutrons 138
Electrons 89
Type Actinide
Isotopes Actinium-227
Discovery Year 1899
Discovered By Friedrich Oskar Giesel
Group 3
Period 7
Boiling Point 1050°C
Melting Point 1050°C
Electron Configuration [Rn] 7s² 6d¹
Density (g/cm³) 10.07
Crystal Structure Hexagonal
Magnetism Paramagnetic
Abundance in Earth's Crust 0.0007%
Phase at Room Temperature Solid
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