Question

Why the Antimony (Sb) has lower ionic radii than As (Arsenic) .
Ionic radii increases going down the group it should increase but gets opposite in the above case why ?

Answer 1

yes I know the reason
the reason is that at the period 4 ( at which antimony is ) the total valence electrons held by shell are 18 and arsenic ( 3rd period ) can hold up to 8 valence electrons , as no. of valence electrons of antimony are more , so attraction with its nucleus ( positive nucleus negative electrons ) increases . thus atomic radii decreases

Answer 2

Answer:

The radius of arsenic which is generally found in books is 222pm which is the radius of -3 oxidation state of arsenic...and radius of antimony which we generally found in books is 76pm which is the radius of +3 oxidation state of antimony because antimony and bismuth are not found in their negative oxidation state...so, it gets opposite because of their oxidation state...

I HOPE IT HELPS..