Final answer:
The lanthanides and actinides are found in the f-block of the periodic table, typically in two rows at the bottom. Lanthanides range from lanthanum (La) to lutetium (Lu), while actinides range from actinium (Ac) to lawrencium (Lr). Both groups are set apart from the main body of the table due to their unique f-orbital electron configurations.
Step-by-step explanation:
Location of Lanthanides and Actinides on the Periodic Table
The lanthanides and actinides are two series of elements known as the f-block of the periodic table. The lanthanide series includes elements with atomic numbers 57 through 71, starting from lanthanum (La) to lutetium (Lu). These are typically located in a separate row at the bottom of the periodic table, just below barium (Ba) and hafnium (Hf). The actinide series comprises elements with atomic numbers 89 through 103, stretching from actinium (Ac) to lawrencium (Lr). This series is typically placed beneath the lanthanide series, following radium (Ra) and rutherfordium (Rf). Both series are characterized by having unfilled f-orbitals; the lanthanides have unfilled 4f orbitals, while the actinides have unfilled 5f orbitals.
Lanthanides are known for their similarity to Group 2 elements and are all metals. The actinides, on the other hand, are all radioactive elements, with only the first four found naturally on Earth and the others synthesized in laboratories. These two groups together are sometimes referred to as inner transition metals. Lanthanum and actinium, though not part of these series based on their electron configurations, are conventionally included due to their chemical properties.