MCQ Detailed View

Cerium (Ce), with atomic number 58, is a member of the f-block elements, which are also called inner transition metals. The f-block consists of lanthanides and actinides, where electrons are being filled in the 4f or 5f orbitals. Cerium belongs to the lanthanide series, characterized by the filling of 4f orbitals.

In the periodic table, the f-block is located below the main body of the table to maintain the table’s structure. Cerium’s electron configuration is:

[Xe] 4f¹ 5d¹ 6s²

This shows that one electron is entering the 4f orbital, confirming that cerium is an f-block element. F-block elements have unique chemical and physical properties due to their partially filled f-orbitals, including variable oxidation states, magnetic behavior, and catalytic activity.

Other options are incorrect:

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  S-block elements have outermost electrons in s-orbitals (groups 1 and 2).

  
  


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  P-block elements have outermost electrons in p-orbitals (groups 13–18).

  
  


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  D-block elements have outermost electrons in d-orbitals (transition metals).

  
  

Understanding that cerium is an f-block element is important in inorganic chemistry for explaining its chemical reactivity, coordination chemistry, and lanthanide contraction. Cerium is widely used in catalysts, alloys, and glass polishing, applications that rely on its f-block characteristics.

Recognizing f-block elements like cerium also helps students understand periodic trends, electron configuration, and the placement of inner transition metals in the periodic table.