Chapter 19: Identification

Question 1

It is the group of atoms in a molecule responsible for the absorption of electromagnetic radiation.

Answer 1

chromophore

Question 2

It is an approximate method of estimating the charge distribution in molecules and complex ions. It states that the distribution of charge in a molecule or ion is such that the charge on any single atom is within the range +1 to -1 (ideally close to zero).

Answer 2

Pauling’s electroneutrality principle

Question 3

It rationalizes the shapes of d-block metal
complexes by considering the repulsions between the groups L. Lone pairs of electrons are ignored. For coordination numbers between 2 and 6, the following arrangements of donor atoms are predicted:

Answer 3

The Kepert model

Question 4

It is one containing three arms, each with a donor atom, which radiate from a central atom or group; this central point may itself be a donor atom.

Answer 4

A tripodal ligand

Question 5

It possess the same connectivity of atoms, but differ in the spatial arrangement of atoms or groups. Examples include trans- and cis-isomers, and mer- and fac-isomers.

Answer 5

Stereoisomers

Question 6

The stereoisomers are not mirror images of one another.

Answer 6

diastereoisomers.

Question 7

Stereoisomers that are mirror images
of one another.

Answer 7

enantiomers.

Question 8

It is the result from the interchange of an anionic ligand within the first coordination sphere with an anion outside the coordination sphere.

Answer 8

Ionization isomers

Question 9

These are possible only for salts in which both cation and anion are complex ions. The isomers arise from interchange of ligands between the two metal centres.

Answer 9

Coordination isomers

Question 10

It may arise when one or more of the ligands can coordinate to the metal ion in more than one way

Answer 10

Linkage isomers

Question 11

These result from the interchange of H2O and another ligand between the first coordination sphere and the ligands outside it.

Answer 11

Hydration isomers

Question 12

A pair of ______________ consists of two molecular species which are non-superposable mirror images of each other

Answer 12

enantiomers

Question 13

Chiral molecules rotate the plane of polarized light

Answer 13

optical activity

Question 14

A mixture of equal amounts of two enantiomers

Answer 14

racemate

Question 15

Name the elements that are collectively known as the
platinum-group metals.

Answer 15

Ru, Os, Rh, Ir, Pd and Pt