What are transition elements and inner transition elements.State the position of the inner transition elements .State why noble gases are considered unreactive elements

Dear Student,

The elements which have partially filled d-orbitals either in ground state or in one or more of their ions are called d-block elements or transition elements. Their properties are intermediate between s-block elements and p-block elements. They are more electropositive than p-block elements but less electropositive than s-block elements. They are all metals and have electronic configuration ns 2 (n-1)d 1 to 10 

Inner Transition elements: These are the f-block elements placed below the periodic table but they belong to 6 and 7 group within the transition series.The electronic configuration of inner transition elements is: (n-2) f 0-14(n-1) d 0-2 ns 2 .These are divided into two series: Lanthanides (atomic numbers 58-71)  and actinides(atomic numbers 90-103).

Position of Inner Transition elements:- 
The Inner Transition Metals are found in the bottom two rows of the periodic table.They include elements Lanthanides (atomic numbers 58-71)  and actinides(atomic numbers 90-103).


By octet rule, any atom participate in a chemical reaction in order to compete  8 electrons in its valence shell.

But the valence shell of noble gases is already full, so they do not participate in any reaction and are unreactive.


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D-block elements are transitional elements and f-block elements are inner transitional elements and innert gases are unreative because they have stable electronic configuration
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