Arrange the following ions in order of increasing ionic radius: iodide ion, cesium ion, telluride ion, barium ion Enter the FORMULA for each ion in the boxes below. Smallest Largest Solution The formula of iodide ion is I - The formula of cesium ion is Cs + The formula of Telluride ion is Te 2- The formula of barium ion is Ba 2+ . These all ions are isoelectric species. That means having the same number of electrons. In isoelectric species ionic radius increases with increasing negative charge on ion and ionic radius decreases with increasing positive charge on ion. Hence the order of increasing ionic radius is as follows: ( Smallest) Ba2 + < Cs + < I- < Te2 - ( largest) .

1. Arrange the following ions in order of increasing ionic radius: iodide ion, cesium ion, telluride
ion, barium ion Enter the FORMULA for each ion in the boxes below. Smallest Largest
Solution
The formula of iodide ion is I -
The formula of cesium ion is Cs +
The formula of Telluride ion is Te 2-
The formula of barium ion is Ba 2+
.
These all ions are isoelectric species. That means having the same number of electrons.
In isoelectric species ionic radius increases with increasing negative charge on ion and ionic
radius decreases with increasing positive charge on ion.
Hence the order of increasing ionic radius is as follows:
( Smallest) Ba2 + < Cs + < I- < Te2 - ( largest)