Question -
Answer -
(a) Each of the given species (ions) has the same numberof electrons (10 electrons). Hence, the given species are isoelectronic.
(b) Theionic radii of isoelectronic species increases with a decrease in themagnitudes of nuclear charge.
Thearrangement of the given species in order of their increasing nuclear charge isas follows:
N3тАУ < O2тАУ тАУ < Na+ 2+ < Al3+
Nuclearcharge = +7 +8 +9 +11 +12 +13
Therefore,the arrangement of the given species in order of their increasing ionic radiiis as follows:
Al3+ < Mg2+ + < FтАУ 2тАУ < N3тАУ