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Explain the bond formation in BeCl_(2) and MgCl_(2). |
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Answer» Solution : `BeCl_(2)` bond formation : (i) ectronic eonfiguration of `Be(Z = 4)" is " " 1s^(2)2s^(2)` and electronic configuration of `Cl (Z = 17) " is " "1s^(2)2p^(6)3s^(2)3P^(5)` (ii) Beryllium has 2 electrons in its valence shell and chlorine atoms (2) have 7 electrons in their valence shell. (iii) By losing two electrons, Beryllium ATTAINS the inert gas configuration of Helium and becomes a dipositive cation, `Be^(2+)` ansd each chlorine atom accepts one electron to become `(Cl^(-))` uninegative ANION and attains the stable electronic configuration of Argon. (iv) Then `Be^(2+)` combine with `2Cl^(-)` ions to FORM an ionie CRYSTAL in which they are held together by electrostatic attractive forces. (v) During the formation of l mole of `BeCl_(2),` the amount of energy released is - 468 kJ/mol. This favours the formation of `BeCl_(2)` and its stabilisation. `MgCl_(2)` bond formation: (i)Electronic configuration of Mg `(z = 12)" is "1s^(2)2s^(2)2p^(6)3s^(2)` Electronic configuration of `Cl (z = 17) " is "1s^(2)2s^(2)2p^(6)3s^(2)3p^(5)` (ii) Magnesium has 2 electrons in ils valence shell and chlorine has 7 electrons in its valence shell. (iii) By losing two electrons, magnesium attains the inert gas configuration of Neon and becomes a dipositive cation `(Mg^(2+))` and two chlorine atoms accept these electrons to become two uninegative anions `[2C1^(-)]` by attaining the stable inert gas configuration of Argon. (iv) These ions, `Mg^(2+) and 2C1^(-)` combine to form an ionic crystal in which they are held together by electrostatic attractive forces. (v) The energy released during the formation of I mole of `MgC1_(2)` is - 783 kJ/mole. This favours the formation of `MgCl_(2)` and its stabilisation. |
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