The elements with atomic numbers 101 and 104 belong to, respectively:
Classification of Elements & Periodicity · Class 11 · JEE Main Previous Year Question
The elements with atomic numbers 101 and 104 belong to, respectively:
- a
Group 11 and Group 4
- b
Actinoids and Group 6
- c✓
Actinoids and Group 4
- d
Group 6 and Actinoids
Actinoids and Group 4
🧠 f-block ends at Z=103; Z=104 starts filling 6d Actinoids are Z = 89 to 103 (filling 5f). After that, the 6d subshell fills — those are d-block elements. For d-block elements, only the outermost s and d electrons determine the group number; filled f-electrons are core electrons.
🗺️ Check each element (Mendelevium): — 5f is filling → Actinoid. (Rutherfordium): — last electron in , group → Group 4.
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