how many groups and subgroups are there longform of theperiodic tables mention any four important features of this table
Answers
Answer :- Long form periodic table called called modern periodic table it consists of 7 periods and 18 groups. It consists of two (2) Sub-groups named as Lanthanides and Actinides.
The four Main features of Modern periodic table are as follows:-
1) Elements are arranged in the increasing order of atomic numbers.
2) Elements in the modern periodic table are arranged in 7 periods and 18 groups.
Horizontal rows are called periods and vertical columns are called groups.
3) Elements are placed in periods based on the number of shells in their atoms.
4) Hydrogen which resemble properties of group 1 alkline metals as well as group 17 halogen elements is given a separate place that is above the group 1 elements of periodic table.
SOME EXTRA POINTS are :-
5) In group IIIB of the sixth period Lanthanides are placed.
6) In group IIIB of the seventh period Actinides are placed
7) In periodic table Lanthanides and Actinides are shown
Explanation:
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