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Ean Rule

Mediumchemistry

Effective atomic number (EAN) of Co in [Co(NO2)(NH3)5]2+ (atomic number of Co = 27) is:

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About This Question

Subject
chemistry
Chapter
coordination compounds
Topic
ean rule
Difficulty
Medium
Year
2025
Tags
EANelectron counting

Solution

Correct Answer:

36

  1. Formula: .
  2. Oxidation State ():
    • Let be . is . is .
    • .
  3. Ligand Donation:
    • One donates electrons.
    • Five donate electrons.
    • Total donation electrons.
  4. Calculation: .
  5. Significance: An EAN of matches the noble gas configuration of Krypton, suggesting high stability.

This medium difficulty chemistry question is from the chapter coordination compounds, covering the topic of ean rule. It appeared in the 2025 exam.

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