Which of the following are isoelectronic species i.e., those having the same number of electrons?
\(Na^+, K^+, Mg^{2+}, Ca^{2+}, S^{2–}, Ar\)
\(Na^+, K^+, Mg^{2+}, Ca^{2+}, S^{2–}, Ar\)
Solution and Explanation
Isoelectronic species have the same number of electrons.
Number of electrons in sodium (Na) = 11
Number of electrons in Na+ = 10
A positive charge denotes the loss of an electron.
Similarly,
Number of electrons in K+ = 18
Number of electrons in Mg2+ = 10
Number of electrons in Ca2+ = 18
A negative charge denotes the gain of an electron by a species.
Number of electrons in sulphur (S) = 16
∴ Number of electrons in S2- = 18
Number of electrons in argon (Ar) = 18
Hence, the following are isoelectronic species:
1) Na+ and Mg2+ (10 electrons each)
2) K+, Ca2+, S2- and Ar (18 electrons each)
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Concepts Used:
Hybridisation
Hybridization refers to the concept of combining atomic orbitals in order to form new hybrid orbitals that are appropriate to represent their bonding properties. Hybridization influences the bond length and bond strength in organic compounds.
Types of Hybridization:
sp Hybridization
sp hybridization is observed while one s and one p orbital inside the identical principal shell of an atom mix to shape two new equal orbitals. The new orbitals formed are referred to as sp hybridized orbitals.
sp2 Hybridization
sp2 hybridization is observed whilst ones and p orbitals of the same shell of an atom blend to shape three equivalent orbitals. The new orbitals formed are referred to as sp2 hybrid orbitals.
sp3 Hybridization
When one ‘s’ orbital and 3 ‘p’ orbitals belonging to the identical shell of an atom blend together to shape 4 new equal orbitals, the sort of hybridization is referred to as a tetrahedral hybridization or sp3.
sp3d Hybridization
sp3d hybridization involves the joining of 3p orbitals and 1d orbital to form 5 sp3d hybridized orbitals of identical energy. They possess trigonal bipyramidal geometry.
sp3d2 Hybridization
With 1 s three p’s and two d’s, there is a formation of 6 new and identical sp3d2 orbitals.