wiz-icon
MyQuestionIcon
MyQuestionIcon
2
You visited us 2 times! Enjoying our articles? Unlock Full Access!
Question

The first ionization enthalpies of 5d elements is higher than that of the corresponding 3d and 4d elements. This is best explained by:

A
Greater extent of metallic bonding in 5d elements
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
Greater effective nuclear charge in the case of 5d elements due to the poor shielding of valence electrons by the 4f electrons
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
C
Neither a nor b
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
Both a and b
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is B Greater effective nuclear charge in the case of 5d elements due to the poor shielding of valence electrons by the 4f electrons
In general, among the s, p d and f orbitals, what is the decreasing order of magnitude of shielding effect on the valence electrons?
For the same principal quantum number, s orbitals electrons do a far better job at shielding the valence electrons from the nucleus than the p orbital electrons. Similarly, the shielding effect of p orbitals screen the valence electrons better than the d orbital electrons and so on.
s > p > d > f (magnitude of shielding effect on valence electrons for the same n)
5d elements have much more nuclear charge and the weakest shielding of valence electrons. Hence their elements experience the maximum electrostatic attraction from the nucleus and thus also have the highest first ionization energies among 3d 4d and 5d elements. Do note that ionization enthalpy is the amount of energy required to remove the most loosely bound valence electron of an isolated gaseous atom to form a cation. So metallic bonding does not come into considerations here!

flag
Suggest Corrections
thumbs-up
9
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Ionization Energy
CHEMISTRY
Watch in App
Join BYJU'S Learning Program
CrossIcon