transition metals

Question 1

why zinc ions are colourless

Answer 1

Zn2+ has a complete D subshell
so electrons cannot be promoted to a higher energy level

Question 2

why scandium and zinc are not transition metals

Answer 2

transition metals form an ion with an incomplete d shell
scandium and zinc are not transition metals
Sc3+: 1s2 2s2 2p6 3s2 3p6
Zn2+: 1s2 2s2 2p6 3s2 3p6 3d10
Sc3+ has an empty d shell
Zn2+ as a dull d shell

Question 3

charge of EDTA

Answer 3

4-

Question 4

which type of bonding exists within [Cr(H2O)6]3+

Answer 4

dative covalent and covalent

Question 5

the six characteristics of transition metals

Answer 5

hard solids
high melting and boiling temperatures
can act as catalysts
form coloured ions and compounds
form ions with incompletely filled d shells

Question 6

ligand definition

Answer 6

a species that uses a lone pair of electrons to form a dative bond with a metal ion

Question 7

co ordination number definition

Answer 7

the number of dative bonds in the complex

Question 8

name of water in complex

Answer 8

aqua

Question 9

name of hydroxide in complex

Answer 9

hydroxo

Question 10

name of ammonia in complex

Answer 10

ammine

Question 11

name of chloride in complex

Answer 11

chloro

Question 12

name of cyanide in complex

Answer 12

cyano

Question 13

name of iron in negative complex

Answer 13

ferrate

Question 14

name of copper in a negative complex

Answer 14

cuprate

Question 15

name of silver in a negative complex

Answer 15

arginate

Question 16

the order of complex ion name

Answer 16

number of ligand
name of ligand
name of the metal ion
oxidation number of the metal ion

Question 17

if there are two ligands, which way should you order them?

Answer 17

alphabetically

Question 18

monodentate ligand

Answer 18

a ligand that forms one dative bond from a lone pair of electrons with a metal ion

Question 19

bidentate ligand

Answer 19

a ligand that forms two dative bonds with a metal ion
e.g. NH2CH2CH2NH2
1,2- diaminoethane: abriviated to en
has optical isomers

Question 20

complex stability

Answer 20

id total number of species (moles) increases across the reaction then stability increases.
entropy increases because ΔS system increases
formation of products is favoured

Question 21

shape of complex with 6 ligands

Answer 21

octahedral
90 degrees

Question 22

shape of complex with 4 ligands

Answer 22

tetrahedral
109.5 degrees

Question 23

shape of complex with two ligands

Answer 23

linear
180 degrees

Question 24

why chloride ion is usually tetrahedral in shape

Answer 24

it is in period 3 so has a large ionic radius
there is insufficient room around the central atom

Question 25

shape of cis platin

Answer 25

square planar

Question 26

reason cis platin is used more than trans platin

Answer 26

trans platin is less effective in treating cancer and is more toxic

Question 27

origin of color in complexes

Answer 27

d shell splits into two levels with different energies
electrons in lower energy absorb energy and promoted to a higher level
amount of energy absorbed depends on the difference between the two levels

Question 28

what causes change in colour of transition metal ions

Answer 28

change in oxidation number
change in ligand (ligand exchange)
change in co ordination number