To identify the correct matches between List-I (Block/group in periodic table) and List-II (Element), we need to understand the characteristics and classification of different blocks of elements in the periodic table:
- Lanthanoid (A): Lanthanoids are elements with atomic numbers from 57 to 71. They belong to the f-block and show similar properties. Cerium (Ce) is a lanthanoid. Therefore, A-I is the correct match.
- d-block element (B): d-block elements are also known as transition metals. Manganese (Mn) is a well-known d-block element. Therefore, B-IV is the correct match.
- p-block element (C): p-block elements include groups 13 to 18 of the periodic table. Arsenic (As) is a member of the p-block elements. Therefore, C-II is the correct match.
- s-block element (D): s-block elements include the first two groups of the periodic table. They consist of alkali metals and alkaline earth metals. Cesium (Cs) is an alkali metal, making it an s-block element. Therefore, D-III is the correct match.
Thus, the correct matching is: A-I, B-IV, C-II, D-III.