Question

Out of these Na+, K+, Al3+ and O2–, which is iso-electronic?
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Answer 1

Iso-electronic species

Iso-electronic species refers to the species which have same number of electrons.

Number of electrons in:

Na+ is 11-1 = 10

K+ is 19-1 = 18

Al 3+ is 13-3 = 10

O 2- is 8+2 = 10

So, Na+ , Al 3+ and O 2- are isoelectronic species.