Electron affinity periodic trends

Electron Affinity movie Periodic Trends Electron Affinity movie... 

Figure 6.22 I The graph shows the electron affinity (in kj/moi) vs. atomic number for the first 20 elements of the periodic table. The inset at the upper right emphasizes the general periodic trend Electron affinity increases —meaning that the value becomes more negative—from left to right and bottom to top in the periodic table.

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. 

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.

Experimentally, electron affinity is determined by removing the additional electron from an anion. In contrast to ionization energies, however, electron affinities are difficult to measme because the anions of many elements are unstable. Table 8.3 shows the electron affinities of some representative elements and the noble gases. The overall trend is an increase in the tendency to accept electrons (electron affinity values become more positive) from left to right across a period. The electron affinities of metals are generally lower than those of nonmetals. The values vary little within a given group. The... 

Account for periodic trends in atomic radii, ionization energies, and electron affinities (Examples 1.11 and 1.12). 

Ionization energy and electron affinity Periodic trends... 

Nonmetals follow the general trends of atomic radii, ionization energy, and electron affinity. Radii increase to the left in any row and down any column on the periodic table. Ionization energies and electron affinities increase up any column and towards the right in any row on the periodic table. The noble gases do not have electron affinity values. Ionization energies are not very important for the nonmetals because they normally form anions. Variations appear whenever the nonmetal has a half-filled or filled subshell of electrons. The electronegativity... 

Sketch an outline of the periodic table and use it to compare the trends in atomic size, first ionization energy, and electron affinity. 

Figure 1.2 Some important trends in the periodic table for (a) ionization energy, (b) electron affinity, (c) atomic and ionic radii, and (d) electronegativity. Increasing values are in the direction of the arrow.

Increasing numbers of protons increase the positive charge of the nucleus, which contributes to electron affinity, the attraction an atom has for an added electron. Electron affinity increases as move you up and to the right on the periodic table. Within a period, the more protons an element has, the stronger its electron affinity tends to be. This trend isn t perfectly smooth because other, more subtle factors cire at work, but it s a good general... 

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. 

For most elements, the first electron gained is exothermic (energy given off). Chlorine s electron affinity (E.A.) is —349 kJ per mole of electrons gained. The higher the first electron affinity (chlorine s is high), the more likely the element is to form an anion. The electron affinities of the elements display loose trends to increase in a period with the atomic number. 

Trends in ionization energy and electron affinity within a period reflect the stability of valence electron configurations. A stable system requires more energy to change and releases less when changed. Note the peaks in stability for groups 2, 13, and 16. 

Increasing Zeff leads to an increase in ionisation energy (IE) across each period. Similar trends are observed in electron affinity (EA). These are shown in figure below ... 

Because of the arrangement of elements on the periodic table, there are several patterns that can be seen between the elements. These patterns, or periodic trends, can be observed for atomic radius, ionic radii, ionization energies, electron affinities, and electronegativities. You should be familiar with the periodic and group trends for each of these. 

Identify periodic trends involving atomic size, ionization energy, and electron affinity. 

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