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Revision notes: Transition Metals chemistry of silver and platinum for A Level Inorganic Chemistry

Periodic Table - Transition Metals - silver and platinum Chemistry - Doc Brown's Chemistry  Revising Advanced Level Inorganic Chemistry Periodic Table Revision Notes

Part 10. 3d block – Transition Metals

10.13 Other Transition Metals e.g. silver and platinum

Aspects of the chemistry of silver and platinum

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All my periodic table (3d-block) advanced level chemistry revision study notes

All my advanced A level inorganic chemistry revision study notes

GCSE Level Notes on Transition Metals (for the basics)

Some of the principal oxidation states of silver and platinum described and examples of redox reactions of silver and platinum, ligand substitution displacement reactions of silver and platinum, balanced equations of silver and platinum chemistry, formula of silver and platinum complex ions, shapes colours of silver and platinum complexes, formula of compounds

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


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] 3d34s2



[Ar] 3d54s1



   [Ar]   3d54s2



[Ar] 3d64s2



[Ar] 3d74s2



[Ar] 3d84s2



[Ar] 3d104s1



[Ar] 3d104s2


31Ga 32Ge
5 37Rb 38Sr 39Y 40Zr 41Nb 42Mo 43Tc 44Ru 45Rh 46Pd 47Ag


48Cd 49In 50Sn
6 55Cs 56Ba 57,58-71 72Hf 73Ta 74W 75Re 76Os 77Ir 78Pt


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.

    • linear1The 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

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10.13b. 3rd d block row - the 5d block elements La, Hf to Hg including the transition metals Hf to Pt, Au

  • Platinum, Pt, Z=78, [Xe]5d96s1 

    • Platinum is a bluish–white lustrous metal that is very malleable and ductile.

    • Platinum is relatively unreactive towards oxygen, water, and most acids, but it will dissolve in oxidising acids like nitric acid.

    • Platinum is used in the manufacture of jewellery because of its attractive appearance and anti–corrosion properties.

    • Platinum is used for thermocouples when alloyed with iridium Ir and Rhodium Rh.

    • Platinum is used for electrical contacts because of ite excellent electrical conductivity and resistance to corrosion.

    • Platinum and platinum compounds are used as catalysts in the chemical industry e.g. in the manufacture of ammonia, nitric acid, sulfuric acid and methanal.

    • Platinum has/is? been used as a catalyst, with rhodium, in catalytic converters of car exhausts to bring about reactions like

      • CxHy (g) + (x + y/4)O2 (g) ===> xCO2 (g) + y/2H2O (g)

      • [to reduce unburned hydrocarbons]

      • 2CO (g) + 2NO (g) ===> N2 (g) + 2CO2 (g)

      • [to reduce oxides of nitrogen and carbon monoxide emissions]

    • Platinum(II) complexes are used to prepare anti–cancer drugs used in chemotherapy.

      • The compound cis–diamminedichloroplatinum(II), [Pt(NH3)2Cl2]0, (known as cisplatin) ...

        • is one of the most effective agents against cancers of the ovaries, bladder, and head and neck and helps as co–agent in the treatment of cancers of the cervix, lung and breast.

        • Its biggest success has been in the treatment of testicular cancer, a form of cancer previously resistant to any therapy but now considered to be curable in most cases.

        • However, cisplatin has three drawbacks which limit its usefulness:

        • (i) It is potentially very toxic,

        • (ii) it only affects a few particular types of tumours and it causes the development of resistance in the tumor cell.

        • The 'clinical point' however, is that you are balancing potentially harmful side effects against possible death.

      • [Pt(NH3)2Cl2]o exhibits a type of isomerism known as E/Z isomerism (once known as cis/trans geometric isomerism),

      • The platinum stereochemistry is very important with the trans isomer showing no anti–cancer activity but the cis–isomer which is pharmacologically very active in its anti–carcinogenic activity (diagram below).

      • [Pt(NH3)2Cl2] diamminedichloroplatinum(II) cisplatin E/Z isomerism cis and trans isomerscisplatin (Z-platin) and transplatin (E-platin), neutral complexes.

      • Z (cis) and E (trans) isomers based on the molecular formula  [Pt(NH3)2Cl2]

      • cis/trans–platin are neutral, square planer complexes of co–ordination number 4, exhibiting geometric isomerism. There of two of each of the monodentate ligands, chloride ion and ammonia and the blue lines/dots show the 4 dative co-ordinate covalent bonds.

      • The cis/trans isomerism is know called E/Z isomerism. In this case E = trans and Z = cis  (in 'old money'!)

      • If the platinum complex was tetrahedral in shape, [Pt(NH3)2Cl2] could not exhibit isomerism of any type.

      • It is the square planar arrangement of four ligands, of two different ligands, that allows the two different spatial positional arrangements.

      • You could not get isomers of this platinum complex if it had a tetrahedral shape, you couldn't form two non-superimposable structures.

      • See  Complexes and isomerism  and  Isomerism in Transition metal complexes

      • Many organic analogues have, and are, being tested for their anti-cancer properties, by replacing  the ammonia group with an aliphatic amine or more complex amines that can act as an electron pair donating ligand.

      • In August 2020 I was recently contacted by a friend who discovered in his house a phial containing 1 g of chloroplatinic acid and wondered if I was interested in it - I was definitely curious, but no longer in a laboratory to make use of it!

      • structure [H3O]+2[PtCl6]2-.xH2O

      • Its a platinum(IV) complex and was used for the gravimetric assaying of potassium.

      • It now finds a use as a catalyst or precatalyst (the latter is converted into the actual catalyst when the reactor is started up!) and is also used in the extraction of platinum from its ores and can be reduced to very pure platinum.

      • Its actually a very valuable compound, costs over £100 per gram or even a lot more!

      • Its now on sale on ebay, where one quote from a Polish source quoted £283 for 1g on ebay!

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


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

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