Reactivity series

If you look at Group 2 in the periodic table, you will see that calcium falls below magnesium calcium is therefore more reactive than magnesium. Sodium falls to the left of magnesium, in the same period sodium is 

by looking at the positions of the elements in the periodic table and their reactions we can build up a reactivity series, with the most reactive elements at the top and the least reactive at the bottom. We can include as many or as few elements as we wish in this series. If we only include the most common elements, we arrive at a list which looks like this  

Such a series is very useful in explaining and predicting the outcomes of various reactions. 

One example is the displacement reaction. Aluminium is more reactive than iron to put it another way, aluminium forms positive ions more easily than iron does. Iron(IlI) oxide is an ionic compound it contains positive iron ions and negative oxygen ions. If you mix aluminium metal with iron oxide, and provide some energy by heating the mixture, the aluminium atoms will give up electrons and force them on to the iron ions, thus converting the iron oxide into metallic iron  

In other words, a more reactive element will displace a less reactive one from its compounds. If, for example, you dip a copper wire into silver nitrate solution and leave it for a while, crystals of silver will start to grow on the copper wire. The copper is more reactive than the silver and forces electrons on to the silver ions, thus converting them into metallic silver atoms  

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Students go on to investigate rates of corrodibility and the reactivity series is introduced. Methods to prevent rusting are considered in a homework exercise and further opportunities to study the methods of rust prevention are provided in two optional lessons. 

Seven chemical reactions were identified from the chemistry syllabus. These chemical reactions were selected because they were frequently encountered during the 2-year chemistiy course and based on their importance in understanding concepts associated with three topics, namely, acids, bases and salts, metal reactivity series and inorganic chemistry qualitative analysis. The seven types of chemical reactions were combustion of reactive metals in air, chemical reactions between dilute acids and reactive metals, neutralisation reactions between strong acids and strong alkalis, neutralisation reactions between dilute acids and metal oxides, chemical reactions between dilute acids and metal carbonates, ionic precipitation reactions and metal ion displacement reactions. Although two of the chemical reactions involved oxidation and reduction, it was decided not to include the concept of redox in this study as students had only recently been introduced to ion-electron... 

Using the metal reactivity series, students are to predict if a chemical reaction would occur when a coil of copper wire is placed in some aqueous silver nitrate in a test-tube. Students are to predict the macroscopic changes that they would expect, given the balanced chemical equation for the above reaction. 

Mayo and Walling, who have given a penetrating critique of the Q,e scheme, point out that it represents in essence merely a transcription to equation form of the reactivity series of Table XX and the po-larity series of Table XXII. Regardless of the manner of interpretation adopted, it is apparent that monomer reactivity in copolymerization depends on two factors. One of these relates to the intrinsic characteristics of the monomer (and of the activated complex produced from it as well) as they tend to favor its addition to a radical. As we have seen, the capacity for resonance stabilization in the transition state is of foremost importance in determining the general level of monomer reactivity. The second factor has to do with the specificity... 

A comparison of this equation with the equations provided above points out that lead (IV) oxide is clearly not a base. The nature of metallic hydroxides varies according to the position of the metal in the reactivity series, as given in Table 6.3. Metallic hydroxides are electrovalent compounds, composed of metal ions, which are positively charged, and hydroxy ions, OTT. The number of OTT ions associated with one metallic ion is equal to the valency of the metal, e.g., Na+OH sodium is monovalent Ca2+(OTT)2 calcium is divalent. The metallic hydroxides form a very important series of compounds, and are known to have many uses both in the laboratory and in industry. 

The torsional effect as propsed by Schleyer57 and steric hindrance of the departing group according to Brown57 both have been discussed as interpretations of these reactivity series. 

The reactivity series ofRF depends on the nature ofX and is I > Br > Cl. In addition, the longer the RF group and the higher the steric hindrance, the lower the yield of l.23 Further, the more hindered RF, the more dimer produced. In order to prepare tetrafluoroalkyl silanes, such fluorinated magnesians must react with alkyl silane halides as follows ... 

Taft and Topsom151 have fairly recently written an extensive review of the electronic effects of substituents in the gas phase. This article includes a tabulation of substituent inductive and resonance parameters. The inductive parameters (designated Op) are based on measured spectroscopic properties in either the gas phase or in hydrocarbon or similar solvents. The resonance parameters were arrived at through the treatment of 38 gas-phase reactivity series by iterative multiple regression, using the cr values of Bromilow and coworkers155 as the starting point. The of value for NO2 was found to be 0.65 (quoted... 

Quantum-Mechanical Prediction of Thermochemical Data Cioslowski, J., Ed. Understanding Chemical Reactivity Series Vol. 22 Kluwer Dordrecht, 2001. 

This particular nucleophilic reactivity series which we find for silicon(IV) is not necessaiily characteristic of what one would expect to find for all different metal ions. And in fact, we know in the case of platinum (I I), where Sn2 reactions seem to occur quite commonly, that we get quite a different nucleophilic reactivity series. The variation in rates for platinum (I I) is almost as large as this. I don t know that an actual range of 109 has been covered yet, but the order of the different nucleophiles is quite different. 

Describe how simple chemical cells can be used to confirm the order of reactivity of the metals in the reactivity series. 

Using the reactivity series Competition reactions in the solid state Competition reactions in aqueous solutions... 

If similar reactions are carried out using other metals with acid, an order of reactivity can be produced by measuring the rate of evolution of hydrogen. This is known as a reactivity series. 

Reactivity series Reaction with dilute acid Reaction with air/oxygen Reaction with water Ease of extraction ... 

Give a use for each of the other unreactive metals shown in the reactivity series. 

The ways in which metal nitrates, carbonates, oxides and hydroxides decompose can also be discussed in terms of the reactivity series of the metals. The decomposition processes are different, depending on the position of the metal in the reactivity series. 

Generally, it is the unreactive metals for which we find most uses. For example, the metals iron and copper can be found in everyday objects such as car bodies and coins, respectively However, the metal aluminium is an exception. Aluminium appears in the reactivity series just below magnesium and is quite reactive. 

The reactivity series is useful for predicting how metals will react. It can also be used to predict the reactions of some metal compounds. The tables on... 

A more reactive metal has a greater tendency to form a metal ion by losing electrons than a less reactive metal does. Therefore, if a more reactive metal is heated with the oxide of a less reactive metal, then it will remove the oxygen from it (as the oxide anion). You can see from the reactivity series that iron is less reactive than aluminium (p. 150). If iron(m) oxide is mixed with aluminium and the mixture is heated using a magnesium fuse (Figure 10.6), a very violent reaction occurs as the competition between the aluminium and the iron for the oxygen takes place. 

In another reaction, metals compete with each other for other anions. This type of reaction is known as a displacement reaction. As in the previous type of competitive reaction, the reactivity series can be used to predict which of the metals will win . 

In a displacement reaction, a more reactive metal will displace a less reactive metal from a solution of its salt. Zinc is above copper in the reactivity series. 

How could you carry out a series of reactions between metals and solutions of their nitrates to establish a reactivity series ... 

This is also a redox reaction involving the transfer of two electrons from the zinc metal to the copper ions. The zinc is oxidised to zinc ions in aqueous solution, while the copper ions are reduced. (See Chapter 5, p. 73, for a discussion of oxidation and reduction in terms of electron transfer.) It is possible to confirm the reactivity series for metals using competition reactions of the types discussed in this section. 

Over the centuries other metals, which like iron are also relatively low in the reactivity series, were isolated in a similar manner. These included copper, lead, tin and zinc. However, due to the relatively low abundance of the ores containing these metals, they were not extracted and used in large amounts. 

Metals high in the reactivity series have proved very difficult to isolate. It was not until more recent times, through Sir Humphry Davy s work on electrolysis, that potassium (1807), sodium (1807), calcium (1808) and magnesium (1808) were isolated. Aluminium, the most plentiful reactive metal in the Earth s crust, was not extracted from its ore until 1827, by Friedrich Wohler (p. 74), and the extremely reactive metal rubidium was not isolated until 1861 by Robert Bunsen and Gustav Kirchhoff. 

Targe lumps of the ore are first crushed and ground up by very heavy machinery. Some ores are already fairly concentrated when mined. For example, in some parts of the world, haematite contains over 80% Fe2Os. However, other ores, such as copper pyrites, are often found to be less concentrated, with only 1% or less of the copper compound, and so they have to be concentrated before the metal can be extracted. The method used to extract the metal from its ore depends on the position of the metal in the reactivity series. 

Metals towards the middle of the reactivity series, such as iron and zinc, may be extracted by reducing the metal oxide with the non-metal carbon. 

How does the method used for extracting a metal from its ore depend on the metal s position in the reactivity series ... 

Bars of zinc are attached to the hulls of ships and to oil rigs (as shown in Figure 10.25a). Zinc is above iron in the reactivity series and will react in preference to it and so is corroded. It forms positive ions more readily than the iron ... 

Metal extraction The method used to extract a metal from its ore depends on the position of the metal in the reactivity series. 

Moderately reactive metals (those near the middle of the reactivity series) are extracted using a chemical reducing agent (for example carbon) in a furnace for example, iron from haematite in the blast furnace. 

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