It will repeat in periodic table with regular intervals ?

1 Answer
Feb 17, 2018

I think you refer to valence electronic structure....and this is responsible for so-called #"periodicity"#...

Explanation:

Look at valence electronic configuration of the alkali metal...#"lithium, Z=3"#, #"sodium, Z=11"#, #"potassium, Z=19"#.

All of these metals have a single valence electron, and upon ionization they form a so-called closed shell inert gas core...i.e. the electronic structure of #Li^+# is equivalent to that of #He#... Since chemistry is based upon the sharing and transfer of electrons, it follows that elements with equivalent valence electronic shells should gives rise to the same sort of chemistry...and indeed they do.

Go to the right hand side of the Periodic Table, as we face it, and we gots the halogens, whose valence shell is ONE electron removed from a Noble Gas configuration... Halogens thus tend to be good oxidizing agents and accept single electrons to form #X^-# ions...

The columns, the Groups of the modern Periodic Table, do reveal the underlying electronic structure...and these clearly are periodic..