Question

Difference between monodentate and polydentate ligand

Answer 1

Denticity refers to the number of times a ligand can bind to a metal atom. A monodentate ligand binds to a metal atom only once. A polydentate ligand binds to the metal atom more than once because it has lone pairs of electrons on more than one atom (also, the atoms that bond to the metal are not directly bonded to each other, which means the ligand "pinches" the metal atom like a claw). Polydentate ligands are often called chelating (KEE-late-ing) agents; the word 'chelating" comes from a root word meaning "claw". 

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