In what periods are the lanthanides and actinides? Where are they placed in the periodic table?
Lanthanides and actinides are in periods 6 and 7, respectively.
Lanthanides and actinides are in periods 6 and 7, respectively. Generally, they are placed underneath the periodic table. The lanthanides are between Barium and Hafnium. The actinides are between Radium and Rutherfordium.