Actinium facts for kids

Quick facts for kids
Actinium, ₈₉Ac

Actinium
Pronunciation	/ækˈtɪniəm/ ​(ak-TIN-ee-əm)
Appearance	silvery-white
Mass number	227
Actinium in the periodic table
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson La ↑ Ac ↓ (Uqu) radium ← actinium → thorium
Atomic number (Z)	89
Group	group 3
Period	period 7
Block	d
Electron configuration	[Rn] 6d1 7s2
Electrons per shell	2, 8, 18, 32, 18, 9, 2
Physical properties
Phase at STP	solid
Melting point	(circa) 1323 K ​(1050 °C, ​1922 °F)
Boiling point	3471 K ​(3198 °C, ​5788 °F)
Density (near r.t.)	10 g/cm3
Heat of fusion	14 kJ/mol
Heat of vaporization	400 kJ/mol
Molar heat capacity	27.2 J/(mol·K)
Atomic properties
Oxidation states	+2, +3 (a strongly basic oxide)
Electronegativity	Pauling scale: 1.1
Covalent radius	215 pm
Spectral lines of actinium
Other properties
Natural occurrence	from decay
Crystal structure	​face-centered cubic (fcc)
Thermal conductivity	12 W/(m⋅K)
Magnetic ordering	no data
CAS Number	7440-34-8
History
Discovery	André-Louis Debierne (1899)
First isolation	André-Louis Debierne (1899)
Main isotopes of actinium
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct 225Ac trace 10 d α 5.935 221Fr 226Ac syn 29.37 h β− 1.117 226Th ε 0.640 226Ra α 5.536 222Fr 227Ac trace 21.772 y β− 0.045 227Th α 5.042 223Fr

Actinium (symbol Ac) is a special chemical element with the number 89 on the periodic table. It's a silvery-white metal that is solid at room temperature.

Actinium is part of the actinide group of elements. It's known for being very radioactive, which means it gives off energy. This strong radioactivity makes it glow with a pale blue light in the dark! Because it's so radioactive, even a small amount needs to be handled very carefully.

History of Actinium

Actinium was found in 1899 by André-Louis Debierne. He was a French chemist. When he first found it, he noticed it was similar to other elements like titanium and thorium.

What Actinium is Like

Actinium is a soft, silvery-white metal. It's very radioactive, which is why it glows blue.

When actinium touches air, it quickly reacts with oxygen and moisture. This forms a white layer called actinium oxide. This layer helps protect the metal from changing further.

Where Actinium is Found

Actinium is very rare. You can only find tiny amounts of it in uranium and thorium ores. These are rocks that contain valuable metals.

How Actinium is Used

Scientists are currently studying actinium for important uses. One main area is in treating cancer. Because it's radioactive, it can be used in a special type of treatment called radiation therapy. This therapy uses radiation to target and destroy cancer cells.

Images for kids

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  Uraninite ores have elevated concentrations of actinium.

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  Chemical structure of the DOTA carrier for 225Ac in radiation therapy.

See also

In Spanish: Actinio para niños