Activity of Metals Show
The Activity of Metals The primary difference between metals is the ease with which they undergo chemical reactions. The elements toward the bottom left corner of the periodic table are the metals that are the most active in the sense of being the most reactive. Lithium, sodium, and potassium all react with water, for example. The rate of this reaction increases as we go down this column, however, because these elements become more active as they become more metallic. Classifying Metals Based on Activity The metals are often divided into four classes on the basis of their activity, as shown in the table below. Common Metals Divided into Classes on the Basis of Their Activity
The most active metals are so reactive that they readily combine with the O2 and H2O vapor in the atmosphere and are therefore stored under an inert liquid, such as mineral oil. These metals are found exclusively in Groups IA and IIA of the periodic table. Metals in the second class are slightly less active. They don't react with water at room temperature, but they react rapidly with acids. The third class contains metals such as chromium, iron, tin, and lead, which react only with strong acids. It also contains even less active metals such as copper, which only dissolves when treated with acids that can oxidize the metal. Metals in the fourth class are so unreactive they are essentially inert at room temperature. These metals are ideal for making jewelry or coins because they do not react with the vast majority of the substances with which they come into daily contact. As a result, they are often called the "coinage metals." Predicting the Product of Main Group Metal Reactions The product of many reactions between main group metals and other elements can be predicted from the electron configurations of the elements. Example: Consider the reaction between sodium and chlorine to form sodium chloride. It takes more energy to remove an electron from a sodium atom to form an Na+ ion than we get back when this electron is added to a chlorine atom to form a Cl- ion. Once these ions are formed, however, the force of attraction between these ions liberates enough energy to make the following reaction exothermic. The net effect of this reaction is to transfer one electron from a neutral sodium atom to a neutral chlorine atom to form Na+ and Cl- ions that have filled-shell configurations. Potassium and hydrogen have the following electron configurations. When these elements react, an electron has to be transferred from one element to the other. We can decide which element should lose an electron by comparing the first ionization energy for potassium (418.8 kJ/mol) with that for hydrogen (1312.0 kJ/mol). Potassium is much more likely to lose an electron in this reaction, which means that hydrogen gains an electron to form K+ and H- ions. AbstractTHE unique role that gold plays in society is to a large extent related to the fact that it is the most noble of all metals: it is the least reactive metal towards atoms or molecules at the interface with a gas or a liquid. The inertness of gold does not reflect a general inability to form chemical bonds, however—gold forms very stable alloys with many other metals. To understand the nobleness of gold, we have studied a simple surface reaction, the dissociation of H2 on the surface of gold and of three other metals (copper, nickel and platinum) that lie close to it in the periodic table. We present self-consistent density-functional calculations of the activation barriers and chemisorption energies which clearly illustrate that nobleness is related to two factors: the degree of filling of the antibonding states on adsorption, and the degree of orbital overlap with the adsorbate. These two factors, which determine both the strength of the adsorbate-metal interaction and the energy barrier for dissociation, operate together to the maxima] detriment of adsorbate binding and subsequent reactivity on gold. This is a preview of subscription content, access via your institution Relevant articlesOpen Access articles citing this article.
Access optionsSubscribe to Journal Get full journal access for 1 year 185,98 € only 3,65 € per issue All prices are NET prices. Buy article Get time limited or full article access on ReadCube. $32.00 All prices are NET prices. Additional access options:
References
Download references Author informationAuthors and Affiliations
Authors
Rights and permissionsAbout this articleCite this articleHammer, B., Norskov, J. Why gold is the noblest of all the metals. Nature 376, 238–240 (1995). https://doi.org/10.1038/376238a0 Download citation
This article is cited byCommentsBy submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate. What is the most active metal?These metals are found in the group I A and II A of the periodic table. As all the given options belong to the same group and the activity increases down the group. So Rubidium is the most active metal.
Is gold a active metal?Gold and silver are active metals.
Which is most active element?Fluorine is chemically the most active element, reacting with virtually every element.
Why is gold the least active metal?Silver or gold are noble metals and are present at the bottom of reactivity series. So, they are inert in nature and are present in their pure form in nature. They do not react with other metals or mineral acids.
|