Answer: fewer unpaired electrons and is low spin.
- A more unpaired electrons and is high spin
- B the same number of unpaired electrons
- C fewer unpaired electrons and is low spin
- D no d electrons at all
Correct answer: C. fewer unpaired electrons and is low spin
Explanation: Both are Fe<sup>3+</sup> (d<sup>5</sup>). H<sub>2</sub>O (weak field) gives high spin, 5 unpaired; CN<sup>-</sup> (strong field) gives low spin, 1 unpaired. So the cyanide complex has fewer unpaired electrons.
The three common coordination geometries: octahedral (6 ligands), tetrahedral (4 ligands), and square planar (4 ligands in one plane).
Concept context
Study of compounds where a central metal atom is bonded to surrounding ligands. Covers nomenclature, types of isomerism, bonding theories (VBT, CFT), and applications in medicine, photography, and industry.