The lanthanides and the actinides make up the f block of the periodic table. The lanthanides are the elements produced as the 4f sub level is filled with electrons and the actinides are formed while filling the 5f sub level
Some significant similarities and differences between lanthanides and actinides are observed. The two rows that are generally placed underneath the main periodic table are called the lanthanides series and the actinides series. These two rows are produced when electrons are being added to f orbitals.
Therefore this block of elements are referred to as the f block. The lanthanides are also occasionally referred to the rare earth elements. Lanthanide and Actinide Series
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The f-block elements in which last electron or differentiating electron enter in (n-2) f-orbitals and the general electronic configuration is (n-2)f1-14(n-1)d0-1 ns2 consists of two series of inner transition elements-
Lanthanides (the fourteen element following lanthanum)
The elements in which the last electron enters one of the 4f-orbitals are called 4f-block elements or first inner transition series. They are also called Lanthanides (or) lanthanones because they come immediately after lanthanum.
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Actinides (the fourteen element following actinium)
The elements in which the last electron enters one of the 5f-orbitals are called 4f-block elements or second inner transition series. They are also called Actinides because they come immediately after actinium. The general electronic configuration is [Rn]5f1-14 6d0-1 7s2
Lanthanides (58Ce- 71Lu) - This series starts from Lanthanum ( atomic numbe r= 57) and continues up to the Lu (Lutetium) as shown in table above. All the elements of the lanthanide series resemble to each other very closely due to the presence of same number of electrons in outermost and the penultimate shells. They are also called rare earth elements. Though Lanthanum is a d-block element but included