How many Periods and Groups are there In the Modem Periodic Table? Also, state what are Lanthanides and Actinides? | web4study

How many Periods and Groups are there In the Modem Periodic Table? Also, state what are Lanthanides and Actinides?



Modem Periodic Table:

In the modern periodic table, there are seven periods and eight main groups.

Each group is sub-divided into ‘A’ and ‘B’ sub-groups.

Elements of Sub-Group ‘A’:

Elements of subgroup ‘A’ are called main or representative elements.

Elements of SubGroup ‘B’:

Elements of SubGroup ‘B’ are called Transition elements.

Lanthanides:

Lanthanides are a group of 14 elements in the 5th period. They are placed at the bottom of the periodic · table. Their electronic configurations display backfilling of 4 f level.

Actinides:

Actinides are also a group of 14 elements in 7th period. They are radioactive element and display filling of Sf level. They are also placed at the bottom of the periodic table.

 


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