Among CrO, Cr2O3 and CrO3, the sum of spin-only magnetic moment values of basic and amphoteric oxides is 10-2 BM (nearest integer). (Given atomic number of Cr is 24 )
877
Acidic character rises with oxidation state: CrO (+2) basic, Cr2O3 (+3) amphoteric, CrO3 (+6) acidic
CrO: Cr2+, 3d4, n = 4 ⇒ = 24 = 4.90 BM
Cr2O3: Cr3+, 3d3, n = 3 ⇒ = 15 = 3.87 BM
∴ sum = 4.90 + 3.87 = 8.77 BM
= 877 10-2 BM
Answer: 877
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