<Li> Extension beyond the 7th period <Ul> <Li> Fricke model <Ul> <Li> large cells </Li> </Ul> </Li> <Li> Pyykkö model </Li> </Ul> </Li> <Ul> <Li> Fricke model <Ul> <Li> large cells </Li> </Ul> </Li> <Li> Pyykkö model </Li> </Ul> <Li> Fricke model <Ul> <Li> large cells </Li> </Ul> </Li> <Ul> <Li> large cells </Li> </Ul>

What are the different groups and periods of the modern periodic table