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Actinide Series

May 20, 2013

actinide series (chem)
The Periodic table has two series. The Lanthanide and Actinides Series. The lanthanide series can be found naturally on Earth. Only one element in the series is radioactive. Actinides Definition: The actinides are unlike the Lanthanide series. All the elements are radioactive and some are not found in nature. Elements with higher atomic number can be made in special laboratory.

Some of these particle accelerators have pounded atomic particles into elements with lower atomic numbers. The buildup of additional parts creates short-lived, high atomic number elements.
The Actinide series contains elements with atomic numbers elements with atomic numbers 89 to 103 i.e. thorium to lawrencium which come immediately after actinium, Z = 89 are called actinides or actinoids. These elements involve the filling of 5 f-orbitals. Their general electronic configuration is,[ Rn ]5 f1-14 6d0-1 7s2 and is in the 3rd group of periodic table. The series is positioned below the Lanthanide series, and is mentioned right below the s, p, and‘d’ groups of periodic table

There is high diversity in oxidation numbers in these series and all are radioactive. The most common and known element is Uranium. Uranium when converted into plutonium, through nuclear reaction, is used as nuclear fuel.
In the periodic table the elements with atomic number 89 through 103 is known as Actinide Series. It has 15 radioactive elements. These elements are in the order of increasing atomic number the first one is actinium followed by thorium, protactinium, uranium, neptunium, plutonium, americium, curium, berkelium, californium, einsteinium, fermium, mendelevium, nobelium, and lawrencium . Out of these actinium, thorium, protactinium, uranium found in nature in appreciable amounts; the remainder have been produced synthetically. The actinide elements show strong chemical resemblance to the rare earth elements. The atomic number of Trans-uranium elements is greater than that of uranium.

In lanthanides the anti penultimate 4f orbitals is filled successively by the addition of one electron at time similarly in actinides the anti-penultimate 5f orbital is successively filled by the addition of one electron at each step. Thus, lanthanides basically involve the 1st inner transition series and the actinides involves the 2nd inner transition series.

Actinides share the following common properties: All Actinides l is radioactive. Actinides are highly electropositive. These metals readily tarnish in air. These Actinides are very dense metals and have distinctive structures.
Numerous allotropes may be formed for example plutonium has at least 6 allotropes.
They react with boiling water or dilute acid to release hydrogen gas. Actinides combine directly with most nonmetals.

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