Larger number of oxidation states are exhibited by the actinoids than those by the lanthanoids, the main reason being
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4f orbitals more diffused than the 5f orbitals
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lesser energy difference between 5f and 6d than between 4f and 5d orbitals
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more energy difference between 5f and 6d than between 4f and 5d orbitals
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more reactive nature of the actinoids than the lanthanoids
