Report on Transition Metals

7/22/2019 Report on Transition Metals

1/4

Physical and chemical properties of transition metals and differences 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. For starters, the

physical and chemical features of 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 electronpair to the metal are called ligands. The ligand is generally neutral, such as H2O, NH3or 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 of the transition metals: Zinc, Copper, Nickel and

Iron. The physical features of the metals (colours and forms ) were recorded. Their magnetic

properties were checked using magnetic stirrer and noted. Finally, a small sample of each 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 solution was


2/4

added until no further change were observed. Samples of Chromium (III) chloride and Chromium (III)

Chloride Anhydrous were provided on the laboratory 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) nitrate hexahydrate was dissolved in 4.0 ml of hot 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 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 retained.

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 Appearance of

elements

Magnetic properties Reactivity with water

Zn Form: bars

Colour: Silver

No magnetic No reactive

Cu Form: bars

Colour: Orange-brown

No magnetic No reactive

Ni Form: powder

Colour: Metallic- grey

Magnetic Forms a layer.

Fe Form: powder

Colour: Grey

Magnetic React very slowly

Part 2

Table 2. Physical characteristic of the transition metal solutions.

Solution (formula) Colour of solution Reaction with ammoniasolution


3/4

Zinc chloride (ZnCl2 ) Colourless White precipitate

Ferric chloride (FeCl3) Yellow Brown-orange precipitate

Nickel chloride (NiCl2) Green Light blue precipitate

Copper sulphate (CuSO4) Light blue Light blue precipitate with a

few drops of ammonia. Adding

more ammonia changes thecolour 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 CrCl3and CrCl3.6H2O.

Complex Colour of complex Reaction with water

CrCl3 Purple, glitter, shinny Not dissolve in water

CrCl3.6H2O Green, not shinny Dissolve in water into green

solution

Regarding to the table 3, CrCl3complex not dissolve in water. Instead, CrCl3.6H2O 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

configuration of Cu: 1s22s

22p

63s

23p

64s

13d

10points that Cu has an unpaired electron and is not

magnetic. Electron configuration of Zn: 1s22s22p63s23p64s23d10indicates that this metal is

diamagnetic because has paired electron and should be magnetic but is not. Electron configuration

of Ni: 1s22s

22p

63s

23p

64s

23d

8and Fe: 1s

22s

22p

63s

23p

64s

23d

6indicate 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.


4/4

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) accordingto their electron configuration.

Documents

Report on Transition Metals