Actinium facts for kids
|Name, symbol, number||actinium, Ac, 89|
|Category notes||sometimes considered a transition metal|
|Group, period, block||n/a, 7, f|
|Standard atomic weight||(227) g/mol|
|Electron configuration||[Rn] 6d1 7s2|
|Electrons per shell||2, 8, 18, 32, 18, 9, 2 (Image)|
|Density (near r.t.)||10 g/cm3|
|Melting point||(circa) 1323 K, 1050 °C, 1922 °F|
|Boiling point||3471 K, 3198 °C, 5788 °F|
|Heat of fusion||14 kJ/mol|
|Heat of vaporization||400 kJ/mol|
|Specific heat capacity||(25 °C) 27.2 J/(mol·K)|
|Electronegativity||1.1 (Pauling scale)|
|Ionization energies||1st: 499 kJ/mol|
|2nd: 1170 kJ/mol|
|Covalent radius||215 pm|
|Crystal structure||face-centered cubic|
|Magnetic ordering||no data|
|Thermal conductivity||(300 K) 12 W/(m·K)|
|CAS registry number||7440-34-8|
|Most stable isotopes|
|Main article: Isotopes of actinium|
Actinium is a silver radioactive, solid metal. It is so radioactive that it glows in the dark. Even a small amount of actinium is dangerous to people.
Actinium is a silvery, radioactive, metallic element. Due to its intense radioactivity, Actinium glows in the dark with a pale blue light. It is found only in traces in uranium ores. One ton of uranium ore contains about a tenth of a gram of actinium.
It is about 150 times as radioactive as radium, making it valuable as a neutron source. Otherwise it has no significant industrial applications. Actinium is used in medicine to produce bismuth in a reusable generator or can be used alone as an agent for radio-immunotherapy.
Actinium was discovered in 1899 by André-Louis Debierne, a French chemist, who separated it from pitchblende. Friedrich Oskar Giesel independently discovered actinium in 1902 and called it "emanium" in 1904. Debierne's name was retained because it had seniority. The chemical behavior of actinium is similar to that of the rare earth lanthanum.
The word actinium comes from the Greek aktis, aktinos, meaning beam or ray.
Images for kids
Uraninite ores have elevated concentrations of actinium
Actinium Facts for Kids. Kiddle Encyclopedia.