The actinide series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium. There are two rows below the Periodic Table, the first row is lanthanides and the second row is actinides.
Actinides
Lanthanides and Actinides are placed separately as the properties of these elements is quite different from the elements in periodic table.
Lanthanides and actinides are placed below the periodic table because of their unique physical and chemical properties.
F-block
Actinides comprise of atomic number 90-103. They are placed at bottom of periodic table.
Rare Earth elements or lanthanides are placed in the period 6 of the periodic table of Mendeleev. Actinoids are placed in the period 7 of the periodic table of Mendeleev.
At the bottom of the Periodic Table
they are not placed from elements 57-70.
Lanthanides and actinides are the two groups that are usually removed from the main body of the periodic table and placed below it to conserve space.
Lanthanides (elements with atomic number 57-71) and actinides (elements with atomic number 89 to 103) are placed at the bottom of the periodic table.
In the periodic table :)
The periodic table of elements is a chart that organizes the elements and emphasizes their shared traits and commonalities. All the known elements and their atomic number are on the periodic table.