In the Modern Periodic Table, the f-block elements are placed separately at the bottom. They are also known as Inner Transition Elements because their last electron enters the anti-penultimate (n-2) f-orbital.
General Formula: (n-2)f¹⁻¹⁴ (n-1)d⁰⁻¹ ns²
Other Name: Inner Transition Elements.
Lanthanides: Fill the 4f orbital (Period 6).
Actinides: Fill the 5f orbital (Period 7, all radioactive).
The general outer electronic configuration for all f-block elements is:
(n-2)f¹⁻¹⁴ (n-1)d⁰⁻¹ ns²
Where:
The f-block consists of two horizontal rows:
1. Lanthanides (4f series)
2. Actinides (5f series)
The general electronic configuration of f-block elements is (n-2)f¹⁻¹⁴ (n-1)d⁰⁻¹ ns².
They are called inner transition elements because the differentiating (last) electron enters the deeply buried (n-2)f orbital, which is two shells inside the outermost shell.
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