The F-orbital is a type of atomic orbital that can hold a maximum of 14 electrons. It is part of the electron configuration in atoms and is characterized by its complex shape, which can be visualized as having multiple lobes. F-orbitals begin to fill in the lanthanide and actinide series of the periodic table, which are located at the bottom of the table. F-orbitals are designated by the quantum number l = 3, indicating their angular momentum. They play a crucial role in the chemical properties of transition metals and inner transition metals, influencing how these elements bond and interact with others in chemical reactions.