Which of the following make an isoelectronic pair: #Cl^-#, #O^(2-)#, #F#, #Ca^(2+)#, #Fe^(3+)#?

1 Answer

Answer:

#Cl^-# and #Ca^(2+)# are isoelectronic

Explanation:

Isoelectronic means "same electronic structure". For atoms, we can say the "same number of valence electrons".

We can assume that if an atom and an ion or two ions have the same number of electrons, they will be arranged in the same shells and subshells.

The calcium and chloride ions both have 18 electrons.