NEET2005Chemistryd and f Block ElementsActual
The main reason for larger number of oxidation states exhibited by the actinoids than the corresponding lanthanoids is:
Options
- Amore energy difference between 5 f and 6 d orbitals than between 4 f and 5 ~d orbitals
- Blesser energy difference between 5 f and 6 ~d orbitals than between 4 f and 5 ~d orbitals
- Clarger atomic size of actinoids than the lanthanoids
- Dgreater reactive nature of the actinoids than the lanthanoids
Correct answer
B. lesser energy difference between 5 f and 6 ~d orbitals than between 4 f and 5 ~d orbitals
Step-by-step solution
In actinides, both 4 f and 5 f orbitals are present. These orbitals poorly shields the nuclear charge due to which the energy difference between the 5 f and the 6 d orbitals will be very low due to which the actinides will show a large number of oxidation states. Caution The elements in which the extra electron enters 5 - orbitals of (n-2)^ th shell (5f-block elements, actinides) shows the maximum oxidation state i.e. +7.