What is the basis of classification of elements in the modern periodic table ?

@ raghav 
the modern periodic table is made as per the atomic number assigned to each and every elemnt . 
its classified on the besic of electronic configuration , 
that is 
1- metals ( s block ) 
2- non metals ( p block ) 
3- transition elemnt ( d block ) 
4- lanthanoids and actinoids ( f block ) 
the 2^nd besic of classification is metallic charecter . 
as we move down the group the metallic charecter increases , 
and conversely , along the period , it will decrease due to decrease in the size of an atom . and increase in electronegativity . 
HOPE IT CLEARS YOUR DOUBT 

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