Periods in the periodic table

There are 7 periods in the standard form of the periodic table:

• Period 1
• Period 2
• Period 3
• Period 4
• Period 5
• Period 6
• Period 7

Period Number

In the standard form of the periodic table the s-block, p-block, and d-block elements are organised into horizontal rows called periods. In WebElements these are labelled from 1 to 7.

The f-block

The f-block elements are assigned to Periods 6 (lanthanoids) and 7 (actinoids) since that is where they are located in the full, or extended, version of the periodic table.