10.13. Other Transition Metals
- Silver and Platinum in particular
Pd |
s block |
d blocks (3d, 4d
block
silver,
5d block
platinum) and
f
blocks of
metallic elements |
p block elements |
Gp1 |
Gp2 |
Gp3/13 |
Gp4/14 |
1 |
1H
|
2 |
3Li |
4Be |
The modern Periodic Table of Elements
ZSymbol, z = atomic or proton
number |
5B |
6C |
3 |
11Na |
12Mg |
13Al |
14Si |
4 |
19K |
20Ca |
21Sc
[Ar]3d14s2
scandium |
22Ti
[Ar]3d24s2
titanium |
23V
[Ar] 3d34s2
vanadium |
24Cr
[Ar] 3d54s1
chromium |
25Mn
[Ar] 3d54s2
manganese |
26Fe
[Ar] 3d64s2
iron |
27Co
[Ar] 3d74s2
cobalt |
28Ni
[Ar] 3d84s2
nickel |
29Cu
[Ar] 3d104s1
copper |
30Zn
[Ar] 3d104s2
zinc |
31Ga |
32Ge |
5 |
37Rb |
38Sr |
39Y |
40Zr |
41Nb |
42Mo |
43Tc |
44Ru |
45Rh |
46Pd |
47Ag
[Kr]4d105s1 |
48Cd |
49In |
50Sn |
6 |
55Cs |
56Ba |
57,58-71 |
72Hf |
73Ta |
74W |
75Re |
76Os |
77Ir |
78Pt
[Xe]4f145d96s1 |
79Au |
80Hg |
81Tl |
82Pb |
7 |
87Fr |
88Ra |
89,90-103 |
104Rf |
105Db |
106Sg |
107Bh |
108Hs |
109Mt |
110Ds |
111Rg |
112Cn |
113Nh |
114Fl |
10.13a.
2nd row 4d block series Y to Cd including Transition Elements Zr to Ag
-
Yttrium, Y,
Z=39, [Kr]4d15s2, is not a true transition
metal and is like scandium Z=21 forming the colourless Y3+(aq)
ion, e.c. = [Kr].
-
Rhodium, Rh, Z=45, [Kr]4d105s1 :
Metal used as catalyst in car exhaust systems (see
platinum below
for more details).
-
Silver, Ag, Z=47, [Kr]4d105s1
-
Silver is a white
lustrous metal that is soft, so very malleable and ductile. and has
the highest electrical and thermal conductivity of any element of
the periodic table.
-
Silver is used
extensively in the electronics industry, jewellery, silverware and
in alloys for use as coinage.
-
Silver is used as a catalyst
in the chemical industry e.g. the production of alkene oxides.
-
Silver compounds are
used in photography (AgCl, AgBr, AgI), antiseptics and for producing
'artificial' rain by seeding clouds with silver salts.
-
The silver(I) ion
forms linear complexes with several ligands.
-
The bond angle
is 180o and
co–ordination number 2 e.g.
-
The water
molecule ligands in the aqueous silver ion [Ag(H2O)2]+(aq)
can be replaced e.g.
-
(i) with ammonia,
NH3,
(neutral ligand) giving a cationic complex,
[H2O→Ag←OH2]+
-
(ii) with the negative cyanide
ion CN–
giving an anionic complex, [NC→Ag←CN]-
-
(iii) the negative thiosulfate
ion S2O32– forming an
anionic complex:
[Ag(NH3)2]+(aq)
solution is used as Tollen's reagent (ammoniacal silver nitrate) in
organic chemistry.
-
The
diamminesilver(I) ion is readily reduced by aldehydes (NOT
ketones) to form a 'silver mirror' on the side of the test
tube on warming the mixture to 60oC.
-
2[Ag(NH3)2]+(aq),
+ 2R–CHO(aq) + 2OH–(aq)
===>
2Ag(s) + 2RCOOH(aq) + 4NH3(aq)
-
So this reaction forms the
basis of a simple test to distinguish aldehydes from ketones.
-
This redox reaction involves
reduction of the silver ion, Ag(+1) to elemental silver Ag(0).
-
The aldehyde is oxidised to a
carboxylic acid.
-
[Ag(CN)2]–(aq)
solution is used in the electrolyte in silver electroplating. The
object to be coated in silver is made the negative cathode
electrode.
-
[Ag(H2O)2]+(aq)
+ 2CN–(aq)
[Ag(CN)2]–(aq)
+ 2H2O(l)
-
The
dicyanosilver(I) ion undergoes
a ligand exchange reaction (water for cyanide ion) without
change in co-ordination number (2), or shape (linear) or
silver's oxidation state (+1).
-
However, although not a
redox reaction, the overall charge on
the silver complex changes from plus (+) to minus (-).
-
The
equilibrium is well over to the right but a very low
concentration of silver ions gives a good even and strongly
adhering surface deposit of silver metal on the conducting
negative cathode electrode.
-
At the
cathode (-) reduction:
[Ag(H2O)2]+(aq) + e– ===> Ag(s)
+ 2H2O(l)
-
The
silver is replenished using a silver anode
-
At the
anode (+) oxidation:
Ag(s) + 2CN–(aq)
– e– ===> [Ag(CN)2]–(aq)
-
[Ag(S2O3)2]3–(aq) is formed when sodium thiosulfate is used to
remove unreacted silver bromide (AgBr) or silver iodide (AgI) crystals in developing
photographic films.
-
AgBr(s) +
2S2O32–(aq)
[Ag(S2O3)2]3–(aq)
+ Br–(aq)
-
This is NOT a redox
reaction, Ag is +1 and Br is –1 throughout the reaction. The
thiosulfate ion is here acting as a ligand and not a
reducing agent e.g. like with iodine.
-
This an example of using
a complex forming reaction to dissolve an insoluble silver
salt.
-
The overall charge of the
silver-thiosulfate complex is 3- (1+ -4)
-
Use of
silver nitrate and ammonia for the halide test is described in the
Chemical Tests Notes for anions
TOP OF PAGE
and sub-indexes
10.13b.
3rd d block row - the 5d block elements La, Hf to Hg including the
transition metals Hf to Pt, Au
keywords redox reactions ligand
substitution displacement balanced equations
formula complex ions complexes ligands colours oxidation states: silver ions Ag+ Ag(+1) 2 [Ag(NH3)2]+, + 2 R–CHO + 2 OH– ==> 2 Ag + 2 RCOOH + 4 NH3 [Ag(H2O)2]+ + 2 CN–
[Ag(CN)2]– + 2 H2O AgBr + 2 S2O32– ==> [Ag(S2O3)2]3– + Br– platinum Pt(0)
Pt2+ Pt(+2)
[Pt(NH3)2Cl2] oxidation states of silver
platinum, redox reactions of silver platinum, ligand substitution displacement
reactions of silver platinum, balanced equations of silver platinum chemistry,
formula of silver platinum complex ions, shapes colours of silver platinum
complexes
WHAT NEXT?
GCSE Level Notes on Transition
Metals (for the basics)
The chemistry of
Scandium
* Titanium * Vanadium
* Chromium
* Manganese
The chemistry of
Iron * Cobalt
* Nickel
* Copper *
Zinc
*
Silver & Platinum
Introduction 3d–block Transition Metals * Appendix
1.
Hydrated salts, acidity of
hexa–aqua ions * Appendix 2. Complexes
& ligands * Appendix 3. Complexes and isomerism * Appendix 4.
Electron configuration & colour theory * Appendix 5. Redox
equations, feasibility, Eø * Appendix 6.
Catalysis * Appendix 7.
Redox
equations
* Appendix 8. Stability Constants and entropy
changes *
Appendix 9. Colorimetric analysis
and complex ion formula * Appendix 10 3d block
– extended data
* Appendix 11 Some 3d–block compounds, complexes, oxidation states
& electrode potentials * Appendix 12
Hydroxide complex precipitate 'pictures',
formulae and equations
Some
pages have a matching sub-index
Advanced
Level Inorganic Chemistry Periodic Table Index:
Part 1
Periodic Table history
Part 2
Electron configurations, spectroscopy,
hydrogen spectrum,
ionisation energies *
Part 3
Period 1 survey H to He *
Part 4
Period 2 survey Li to Ne * Part
5 Period 3 survey Na to Ar *
Part 6
Period 4 survey K to Kr AND important
trends down a group *
Part 7
s–block Groups 1/2 Alkali Metals/Alkaline Earth Metals *
Part 8
p–block Groups 3/13 to 0/18 *
Part 9
Group 7/17 The Halogens *
Part 10
3d block elements & Transition Metal Series
*
Part 11
Group & Series data & periodicity plots
All
11 Parts have
their own sub-indexes near the top of the pages
Group numbering and the modern periodic
table
The original group numbers of
the periodic table ran from group 1 alkali metals to group 0
noble gases. To account for the d block elements and their
'vertical' similarities, in the modern periodic table, groups 3
to group 0 are numbered 13 to 18. So, the p block elements are
referred to as groups 13 to group 18 at a higher academic level,
though the group 3 to 0 notation is still
used, but usually at a lower academic level. The 3d block
elements (Sc to Zn) are now considered the head (top) elements
of groups 3 to 12.
Website content © Dr Phil Brown
2000+. All copyrights reserved on revision notes, images, quizzes,
worksheets etc. Copying of website material is NOT permitted. Doc
Brown's Chemistry theoretical-physical chemistry revision notes for
pre-university level students on d-block elements including the
physical and chemical properties reactions equations and trends
explained for the 3d-block of transition metals series
|
|
|