Question

What is the name of the molecules or ions that surround the metal in a complex ion?

Select one:

a. Chelaters

b. Donors

c. Acceptors

d. Coordinators

e. Ligands

Answer 1

A coordinate complex has a transition metal and ligands are arranged around it.

Therefore the answer for above question is ligands.That is option(e) is correct.

The explanation for above answers is:-

Metals are electrons deficient in nature due to vacant d-orbitals.That's why metals have tendency to accept electrons in the coordination complex.Since they have the ability to accept electrons they act as lewis acid.

But ligands have excess electrons and they have the tendency to donate electrons to the metal in the coordination complex.That's why they are called as lewis base.

So ligands have donor ability.But all the donors are not ligand.

Some ligands have more than one donor atoms which can donate electrons to the metal ion in the coordination complexes.Those ligands which have more than one donor atom are called polydentate ligands or chelating ligands.

Its not always necessary for the metal in coordination complex to accept electrons from chelating or polydentate ligand.Metal forms coordination complex with monodentate ligands too and monodentate ligands are not chelators.

Thats why the species surrounding the metal ion in the coordination complex are donors which may be chelators or not.As a whole the species surrounding the metal ion in the coordination complex are called ligands.Donor ability and chelating are the properties of the ligands.