Common shapes of complexes

Question 1

six-fold coordination refers to

Answer 1

refers to complexes in which there are six ligands forming coordinate bonds with the transition metal ion

Question 2

each ligand uses ………………… lone pair(s) of electrons to form a coordinate bond even though each ligand may have a different number of ……………..
NH3 has ……..pairs
H2O has ……………pairs
OH- has ……pairs

Answer 2

• each ligand uses 1 lone pair to form a coordinate bond
• different ligands may have different numbers of lone pairs

NH3 3 lone pairs
H2O 2 lone pairs
OH- 1 lone pairs

Question 3

the electron pair donor in each of these ligands is an element in ………………..meaning

Answer 3

an element in Period 2 of the Periodic Table, meaning they are of approximately equal size

Question 4

The name and colour of the following ions are:

[Mn(H2O)6]2+

[Fe(H2O)4(OH)2]

[Al(OH)6]3-

Answer 4

[Mn(H2O)6]2+
hexaaquamanganese(II), very pale pink (usually described as colourless
[Fe(H2O)4(OH)2]
tetraaquadihydroiron(II), pale green

[Al(OH)6]3-
hexahydroaluminate(III), colourless
this last example is not a transiiton elemnt, or a d-block element, but this name can be predicted in the same way as complex of non-transition metals

Question 5

when chloride ions act as ligands, the common shape they form is…………….because

Answer 5

tetrahedral complex because chlorine is a Period 3 element, so its ions are much larger than water, ammonia and hydroxide ions, so there is usually insufficient room around the central metal ion for six chloride to act as ligands

Question 6

the reactive ion present in Tollen’s reagent is

Answer 6

the linear complex, [H3N -Ag - NH3]