Physical and chemical properties properties of transition metals and differences between between the transition metals complexes. Preparation of a transition metal complex with a knowledge about physical and chemical features of the transition metals and their complexes. Aims
The main aim of this experiment is preparation of the transition metal complex. complex. For starters, the physical and chemical features of o f transition metals and their complexes need to be determined. to determine physical properties of the transition metals, how the transition metal complexes behave in contact with ammonia, differences between Chromium( III) Chloride Anhydrous and Chromium ( III) Chloride, prepare a simple transition metal complex.
Introduction
The transition metals they are metals which make the transition to using the d-orbital for their bonding . The first row d-block elements are all to reactive to occur naturally as free metals and they form compounds with oxide ores and sulphide ores. Transition metals form one or most stable ions which has incompletely filled d-orbital. Lewis bases which bond to metal ion and donate an electron pair to the metal are called ligands. The ligand is generally neutral, such as H 2O, NH3 or anionic such -
as Cl . The ligand coordinate to the metal ion to give a complex. In the first part of the experiment the properties of the example of the transition metals will demonstrated. It will be also observed and recorded how the transition metals complexes react with ammonia and water. In the last part of the experiment the transition metal complex will be prepared and IR spectrum will be recorded.
Methods Part 1
On the laboratory bench there were samples samples of the transition transition metals: Zinc, Copper, Nickel and and Iron. The physical features of the metals (colours and forms ) were recorded. Their magnetic properties were checked using using magnetic stirrer and noted. Finally, a small sample of each metal metal was tested how it react with water. Part 2 Solution of Zn, Cu, Ni and Fe sulphates and chlorides were provided on the laboratory bench. A small sample of each of these metals were taken and a few drops of the ammonia solution were added at a time. The physical characteristics of the solutions were recorded. Then ammonia so lution was
added until no further change were observed. Samples of Chromium (III) chloride and Chromium (III) Chloride Anhydrous were provided on the l aboratory desk. The differences between them were studied and recorded. Firstly 1.006g of CrCl3.6H2O was added to 50ml of water, then the solution was stirred using a stirrer hot plate. The observed details, what happens with solution were recorded. Then an examination of 1.036 g of CrCl3 and an ammonia solution was repeated. Part 3 In this section of the experiment, a simple transition metal complex was prepared. First, in 25 ml conical flask, 3.084g of Ni (II) (II) nitrate hexahydrate was dissolved in 4.0 ml of hot industrial industrial methylated spirits (IMS) under stirring. In a separate flask, 2.026 g of KSCN was also dissolved in 4ml of IMS. Then, two solution were combined under stirring and 10 ml of IMS were added to them. The mixture were cooled and a solid so lid material was formed. Next, the resultant solid was isolated by vacuum filtration and washed with a small volume of IMS. The filtrate ( green liquid ) was re tained. In a third conical flask, a 1:1 (by volume) mixture OF IMS and water was made and heated up gently. 3.804 g KSCN was dissolved in a small volume of the IMS/water mixture. Once the KSCN has dissolved completely, the filtrate from the previous experiment was added and the mixture was transferred to a large beaker. The beaker was placed on a steam bath in the fume cupboard until the solvent volume has been reduced to around 5ml. Then, the solution was cooled in an ice bath and after a few minutes, crystals were started to form. The solution was left for 20 minutes in the ice bath to form crystals and then were recovered by vacuum filtration. The mass of the product and the IR spectrum were recorded.
Results 1
Part 1 Table 1. Physical characteristics of transition metals. Elements Zn Cu Ni Fe
Appearance of elements Form: bars Colour: Silver Form: bars Colour: Orange-brown Form: powder Colour: Metallic- grey Form: powder Colour: Grey
Magnetic properties
Reactivity with water
No magnetic
No reactive
No magnetic
No reactive
Magnetic
Forms a layer.
Magnetic
React very slowly
Part 2 Table 2. Physical characteristic of the transition metal solutions. Solution (formula)
Colour of solution
Reaction with ammonia solution
Zinc chloride (ZnCl2 ) Ferric chloride (FeCl3) Nickel chloride (NiCl2) Copper sulphate (CuSO 4)
Colourless Yellow Green Light blue
White precipitate Brown-orange precipitate Light blue precipitate Light blue precipitate with a few drops of ammonia. Adding more ammonia changes the colour into more blue and solution dissolve in ammonia.
As indicates the table 2 all solutions not dissolve in ammonia. Only Copper sulphate dissolve completely in ammonia making blue solution. ZnCl2+NH3 Table 3. The differences between CrCl 3 and CrCl 3.6H2O. Complex CrCl3 CrCl3.6H2O
Colour of complex Purple, glitter, shinny Green, not shinny
Reaction with water Not dissolve in water Dissolve in water into green solution
Regarding to the table 3, CrCl 3 complex not dissolve in water. Instead, CrCl 3.6H2O dissolve in water completely. Part 3
Analysis:
As indicates the table 1 all transition metal not react with water or react very, very slowly. Considering magnetism data, Zinc and Copper do not indicate magnetic features but Nickel and Iron are magnetic. The magnetic properties of elements depend on their electronic configuration. Atoms and molecules with unpaired electrons are paramagnetic and are not magnetic. Electron 2
2
6
2
6
1
10
configuration of Cu: 1s 2s 2p 3s 3p 4s 3d points that Cu has an unpaired electron and is not 2
2
6
2
6
2
10
magnetic. Electron configuration of Zn: 1s 2s 2p 3s 3p 4s 3d indicates that this metal is diamagnetic because has paired electron and should be magnetic but is not. Electron configuration 2
2
6
2
6
2
8
2
2
6
2
6
2
6
of Ni: 1s 2s 2p 3s 3p 4s 3d and Fe: 1s 2s 2p 3s 3p 4s 3d indicate that these metals are diamagnetic because have paired electrons and they expect to be not attracted into magnetic field but according to my results they are magnetic.
Structure of the starting material (Ni (II) nitrate hexahydrate )
Conclusion
In this laboratory experiment, the physical characteristic of the transition metals were determined. Our result indicates that some of the metals should have different properties (magnetizm) according to their electron configuration.
