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What is electrovalent (Ionic) bond ? Explain with any two example.

Answer»

Solution :Electrovalent Oonic) bond : The bond formed, as a result of the electrostatic attraction between the positive and negative ions was termed as the electrovalent bond.
Example-I : IONIC bond formation in sodium chloride (NaCl)
Na (Alkali metal) is highly electropositive metal and form Na+ ion by loss of one electron and attain stable noble gas electronic configuration
`underset([Ne]3s^(1))(Na) rarr underset([Ne])(Na^(+)) + e^(-)` .
Chlorine is the highly electronegative halogens. It convert into `Cl^(-)`negative ion by gain one electron of sodium ion. This `Cl^(-)` ion attain stable electron configuration of noble gas AR `(3s^(2)3p^(6))`.
`underset([Ne] 3s^(2) 3p^(5)) + e^(-) rarr "" underset([Ar] " or " [Ne] 3s^(2) 3p^(6))(Cl^(-))`
Thus, `Na^(+)` positive ion and `Cl^(-)` negative ion both have stable outer shell configuration of eight (octet) electrons. And between them ionic (electrovalent) bond is formed.
`Na^(+) + Cl^(-) rarr " NaCl or " [Na^(+) Cl^(-)]`
Example-2 : Ionic bond (electrovalent) formation in `CaF_(2)`.
The calcium loses TWO electrons to attain the stable noble gas configuration of argon and converted into `Ca^(2+)`calcium.
`underset([Ar]4s^(2))(Ca) rarr underset([Ar])(Ca^(2+)) + 2e^(-)`
The halogen atom fluorine can gain highly electronegative one electron to require the stable outer shell configuration and convert into fluoride ion.
`underset([He]2s^(2) 2p^(5))(F) +e^(-) rarr underset([He]2s^(2) 2p^(6)"or"[Ne])(F^(-))`
The positive ion `Ca^(2+)` and negative ion `F^(-)` ion are held TOGETHER by strong electrostatic force of attraction and formed electrovalent bond containing `CaF_(2)`.
`Ca^(2+) + 2F^(-1) rarr CaF_(2) `


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