Periodic property electron affinities

Figure 8.1 S Trends in three atomic properties. Periodic trends are depicted as gradations in shading on miniature periodic tables, with arrows indicating the direction of general increase in a group or period. For electron affinity. Group 8A0 8) is not shown, and the dashed arrows indicate the numerous exceptions to expected trends.

Electron affinity and metallic character also exhibit periodic trends. Electron affinity is a measure of how easily an atom will accept an additional electron and is crucial to chemical bonding because bonding involves the transfer or sharing of electrons. Metallic character is important because of the high proportion of metals in the periodic table and the large role they play in our lives. Of the roughly 110 elements, 87 are metals. We examine each of these periodic properties individually in this section. 

The Periodic Table forms one of the most remarkable, concise, and valuable tabulations of data in science. Its power lies in the regularities that it reveals, thus, in some respects, it has the same role as the SOM. Construct a SOM in which the input consists of a few properties of some elements, such as electronegativity, atomic mass, atomic radius, and electron affinity. Does the completed map show the kind of clustering of elements that you would expect What is the effect of varying the weight given to the different molecular properties that you are using ... 

The goal of this chapter is to help you relate the properties of elements to their position on the periodic table. These properties include ionization energies and electron affinities. You may want to review the basic structure of the periodic table in Chapter 2 and electron configurations in Chapter 7. And Don t forget — Practice, Practice, Practice. 

The most obvious chemical significance of the electronic structure of atoms lies in the factors that determine ionization energies, electron affinities, and the sizes of atoms. This section looks briefly at some of the trends— vertically and horizontally in the periodic table—in such properties. 

As you can see in Figure 3.6, electronegativity is a periodic property, just as atomic size, ionization energy, and electron affinity are. Atomic size, ionization energy, and electron affinity, however, are properties of single atoms. In contrast, electronegativity is a property of atoms that are involved in chemical bonding. 

We have developed a fairly complete picture of polyelectronic atoms that is quite successful in accounting for the periodic table of elements. We will next use the model to account for the observed trends in several important atomic properties ionization energy, electron affinity, and atomic size. 

Diagonal relationships in the periodic table exist as well as the vertical relationships. For example, Be and Al are similar in some of their properties, as are B and Si. Rationalize why these diagonal relationships hold for properties such as size, ionization energy, and electron affinity. 

Electron affinity is another periodic property of the elements. Research and write a report on what electron affinity is and describe its group and period trends. 

The Hartree orbitals and the shell model explain periodic trends in ionization energy, electron affinity, and the radii of atoms and ions. Small changes in these properties within a period are further explained by detailed changes in Z ff within that period. 

This chapter describes the connections between the one-electron configurations of the elements, the structure of the Long Form of the Periodic Table and the physical properties of the elements, namely their size, ionisation energies and electron affinities or attachment enthalpies. 

The main variations of properties of the elements that are summarised in the Periodic Table can be divided into physical and chemical properties. These will be briefly described with the elements restricted to the first four rows of the Periodic Table in order to conserve space. The three most important physical properties of the elements are their size, ionisation potential and electron affinity or attachment enthalpy each of these will be discussed briefly. 

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