Question

Order of Al+3 ,Mg+2, F-,O-2

Answer 1

a) Each of the given species (ions) has the same number of electrons (10 electrons). Hence, the given species are isoelectronic, i.e

N3- has 7+3 = 10 electrons

O2- has 8+2= 10 electrons

F- has 9+1 = 10 electrons

Na+ has 11-1 = 10 electrons

Mg2+ has 12-2 = 10 electrons

Al3+ has 13-3= 10 electrons

(b) The ionic radii of isoelectronic species increases with a decrease in the magnitudes of nuclear charge.

The arrangement of the given species in order of their increasing nuclear charge is as follows:

N3– < O2– < F– < Na+ < Mg2+ < Al3+

Nuclear charge = +7 +8 +9 +11 +12 +13

Therefore, the arrangement of the given species in order of their increasing ionic radii is as follows:

Al3+ < Mg2+ < Na+ < F– < O2– < N3–