Question

how to find group and period from electronic configuration of an element

Answer 1

The period of an element corresponds to the principal quantum number of the Valence shell. The block of an element corresponds to the type of orbital which receive the last electron. For s-block elements , group number is equal to the number of valence . please mark me as brainless

Answer 2

hello,
Period depend upon the valency of the particular element.and valency is one of the main reason resposible for their position in perodic table.
for example-li (lithium) its atomic no. is 3
so its electronic configuration is 2,1
hence its valency is 1.
thus it is a first group element.
hope it helps
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