Question

The isoelectronic pair is

• A. $C{l}_{2}O,IC{l}_2^{-}$
• B. $C{l}_2^{-},Cl{O}_2$
• C. $I{F}_2^{+},I_3^{-}$
• D. $Cl{O}_2{}^{-},Cl{F}_2^{+}$

Answer 1

Answer: (D)

Isoelectronic species are elements or ions that have the same or an equal number of electrons.
A. $)C{l}_{2}O=2\times 17+8=42$ electrons
$IC{l}_2^{-}=53+2\times 17+1=88$ electrons
B. ) $C{l}_2^{-}=2\times 17+1=35$ electrons
$Cl{O}_2=17+2\times 8=33$ electrons
C. $)I{F}_2^{+}=53+2\times 8-1=68$ electrons
$I_3{}^{-}=53\times 3+1=160$ electrons
D. ) $Cl{F}_2^{+}=17+2\times 9-1=34$ electrons
$Cl{O}_2^{-}=17+2\times +1=34$ electrons
$Cl{O}_2^{-}$and $Cl{F}_2^{+}$contain 34 electrons.
Hence option D contains the same number of electrons. Therefore, they are isoelectronic.