Affinity, generally

Ionic size tends to increase down groups and decrease across periods. Electron affinity generally decreases down groups and increases across periods. 

Ionization energy, electronegativity, and electron affinity generally increase as you move across a period and decrease as you move down a group. 

Electron affinities generally decrease down a group. 

Electron affinities generally increase across a period. 

The energy released when a single electron is added to a neutral atom in the gaseous state is known as the electron affinity. Electron affinities generally decrease proceeding down a group and increase proceeding across a period. 

The stability of profein complexes is measured by the binding constant (Ka). Experimentally determined values of Ka span over 10 orders of magnitude (see Figure 4.1). It is clear that no simple correlations exist between structures of protein complexes and their binding affinities. General approaches to calculating binding affinities have been reviewed [14]. Here we focus on aspects specific to protein-protein and protein-nucleic acid complexes. 

The first process begins with a neutral atom, whereas the second begins with a positive ion. Thus, IE and EA are not simply equal in value with the signs reversed. We see from Figure 5-3 that electron affinities generally become more negative from left to right across... 

First electron affinities generally correlate with electronegativity (Chapter 3). The halogens show clear trends in electronegativity and electron affinity (with the exception of fluorine, which has an unexpectedly low electron affinity) (Table 15.1). 

Electron affinity is defined as the amount of energy required to remove an electron from a negative ion that is in the gaseous state. Since metals tend not to form negative ions, electron affinity really only applies to nonmetals. The trends for electron affinity are similar to the trend for ionization energy. As we move across a row of the periodic table from left to right, electron affinity generally increases. As we descend a column, electron affinity tend to decrease. 

Electron affinity generally becomes more negative (adding an electron becomes more exothermic) as we move to the right across a period (row) in the periodic table. 

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