1yes perfectly.... dats the inert pair effect...
can u tell me y the following trend is difft.
d 1st ionization enthalpy values of gp 13th
B Al Ga In Th
801 577 579 558 589
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UP 0 DOWN 0 0 3
3 Answers
1Ionisation enthalpy generally decreases down the group. But in this case there is a slight increase in the case of Ga and Th. This is because in case of Ga , 3d subshell is present and in case of Th, 4f subshell is present.
3d and 4f provide poor shielding, so they can't account for the increase in nuclear charge ( which has increased more due to presence of 3d elements and 4f elements resp ).
Therefore , I.E. is more in case of these two..
1by slater's rule,
Z* = Z - shielding constant...
from the values of Z* we can infer the that as there is a dec in value of Z* (Z=atomic no.) there's inc in nuclear charge ... so I.E. is more.