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Explainionizationenthalpy and electronegativity for elements of Boron family. |
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Answer» Solution :Ionization enthalpy : The ionisation enthalpy values as expected from the GENERAL trends do not decrease smoothly down the group . The decrease from B to AL is associated with increased in size. The observed discontinuity in the ionisation enthalpy values between Al and Ga and between In and Tl are due to inability of d- and f- ELECTRONS, which have low SCREENING effect, to compensate the increase in NUCLEAR charge. The order of ionisation enthalpies , as expected , is `Delta_i H_1 lt Delta_i H_2 lt Delta_i H_3`. Electronegativity :Down the group , electronegativity first decreases from B to Al and then increases marginally. This is because of the discrepancies in atomic size of the elements. |
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