Question

How does the electronic configuration of an atom relate to its position in the Modern Periodic table?

CONTENT QUALITY REQUIRED

Answer 1

Relation between the electronic configuration and modern periodic table:
1) The last digit in the electronic configuration depicts the group number for Group 1 and Group 2 elements. For example ---
Lithium ( Li) --- Electronic Configuration--2,1
Therefore Lithium belongs to group 1
Calcium (Ca) ---Electronic Configuration-- 2,8,8,2
Therefore Calcium belongs to group 2

2) The Total no of digits indicate the period number.

(N.B) Only Valid for elements having atomic number from 1 to 20 .

For Example- - Calcium (Ca)--- Electronic Configuration--- 2,8,8,2
Therefore no. of digits = 4
Therefore Period number of Calcium is 4

3) For Elements having 3 to 7 electrons in the outermost shell ( valence shell) ,The group no.can be determined by adding 10 with that number.

For example---Nitrogen---Electronic Configuration--- 2,5
Now 5+10 = 15
Therefore Nitrogen belongs to group 15 .
Another example- - Aluminium (Al)--Electronic Configuration---2,8,3
Now 3+10=13
Therefore Aluminium belongs to group 13

I Hope This Helps.
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Answer 2

Electronic configuration is defined as the arrangement of electrons in the different energy levels of an atom .

Electronic configuration determines :-

1) the period number -

the number of shells signifies the period number
Ex - Li [ 1s2 2s1 ] has 2 shells therefore belongs to 2nd period

2) the group number -

the number of valence electrons signifies the group number .
Ex - Be [1s2 2s2] has 2 valence electrons hence belongs to group 2

3) block number -

the block number can be determined by observing to which orbital the last electron enters .
Ex - C [1s2 2s2 2p2 ] . the last electron enters the p orbital and hence it is a p-block element

hope it helps :-)