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Shweta Thakur posted an Question

June 02, 2021 • 15:50 pm

30 points

IIT JAM
Chemistry (CY)

Lanthunum and actinium are d block or f block

lanthunum and actinium are d block or f blocked hxkg khzjgJfsktzykzoyz

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Bhagat singh 1

answer.
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Dinesh khalmaniya 1

these arr d block elements we we study of these elements with F block elements explanation- We designate an element as d-block or f-block based on the subshell into which the differentiating electron enters. Barium preceedes Lanthanum. When we go from Barium to Lanthanum, an electron enters into an orbital belonging to d subshell. Same is the case when we go from Radium to Actinium. Hence both Lanthanum and Actinium are d-block elements. In the next 14 elements (cerium to lutetium) after Lanthanum, the differentiating electron enters into the f-subshell. Thus these 14 elements belong to f-block. Same is the case with Actinium. Thus there are 28 elements (14*2) in f-block.
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Priyanshu kumar Best Answer

Lanthanum and Actinium are generally both accepted as f-block elements. You will notice in the Royal Society's periodic table, La and Ac are both color coded to match the other f-block elements. They do this to show the beginning of both the Lanthanide and Actinide series, while maintaining a reasonable symmetry for their periodic table
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Both Lanthanum and Actinium placed in the d-block although they are f-block elements just because their d orbital is not completely filled and before the filling of the d orbital f orbital starts to get filled . Since the f orbital of lanthanum and actinium is empty thus they are kept with the d lock elements but are considered as the beginning of the f block elements. Hence they are considered as the part of the d block elements.
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