MCQ Detailed View

The electronic configuration of an element shows the arrangement of electrons in its orbitals. This helps determine its position in the periodic table and its classification into s, p, d, or f blocks. The given configuration is [Kr] 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹ 6s². Breaking this down step by step, the important observation is the completely filled 4f orbital, which contains 14 electrons. The f-subshell is a characteristic feature of the f-block elements.

Elements in the f-block are also known as inner transition elements and include the lanthanides and actinides. They are characterized by the gradual filling of the 4f and 5f orbitals. In this configuration, the 4f orbital is completely filled, showing that the element lies at the boundary between the f-block and d-block regions. Such configurations are typical for elements placed immediately after the lanthanide series, where the f-orbitals are fully filled.

Although a 5d electron is also present, the strong presence of the filled 4f subshell places this element in the category of f-block. F-block elements have special properties: they commonly show variable oxidation states, form colored compounds, and are widely used in industries ranging from nuclear technology to catalysts and magnets.

To avoid confusion, it is important to remember the general rule: if the electron configuration involves the filling of the f-orbital, the element belongs to the f-block. Since this configuration clearly contains a completely filled 4f¹⁴, the element is classified under the f-block.

Thus, based on the orbital filling pattern and periodic classification, the correct answer is the f-block.