Why are the first ionization energies of some of the group 13 elements smaller than the first ionization energies of the nearby alkali earth metals in the same period?
A. There is a decrease in shielding by inner-shell electrons and a decrease in atomic size.
B. There is an increase in shielding by inner-shell electrons and an increase in atomic size.
C. It is easier to remove an electron in a p orbital than an s orbital because it experiences less effective nuclear charge.
D. It is easier to remove an electron in an s orbital than a p orbital because it experiences less effective nuclear charge.
The correct Answer is C. It is easier to remove an electron from p orbital than s orbital because it experiences less effective nuclear charge.
The general electronic configuration of group 12 elements is.gif)
while that of group 13 elements is.gif)
. The outer most electron in group 13 element is in p orbital while in group 12 is in s orbital. Since 2s electrons are more penetrating towards the nucleus than 2 p electrons, therefore, lesser amount of energy is required to knock out a 2p electron than a 2s electron.
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while that of group 13 elements is.gif){kind=small}
. The outer most electron in group 13 element is in p orbital while in group 12 is in s orbital. Since 2s electrons are more penetrating towards the nucleus than 2 p electrons, therefore, lesser amount of energy is required to knock out a 2p electron than a 2s electron.