Elements electron affinity

Atomic number Element Electron affinity kJ mol ) Total... 

Symbol Br atomic number 35 atomic weight 79.904 a halogen group element electron affinity 3.36359 eV electronegativity 2.8 electron configuration [Ar] 3di°4s24p5 most stable valence states -1 and -i-5, less stable valence states -1-1 and -i-3 a diatomic molecule (Br2) in liquid and vapor states over a wide range of temperature two stable isotopes, Br-79 (50.57%) and Br-81 (49.43%). 

Element Electron affinity, eV Element Electron affinity, eV ... 

Figure 9.1 Electron affinities of the elements, electron affinities, and bond dissociation energies of the homonuclear diatomic molecules in the form of a Periodic Table [1],...

Element Electron affinity Element Electron affinity... 

Element First Ionization Energy Element Electron Affinity... 

The groups and periods of the periodic table display general trends in the following properties of the elements electron affinity, electronegativity, ionization energy, atomic radius, and ionic radius. 

Typical elements in Groups V. VI and VII would be expected to achieve a noble gas configuration more easily by gaining electrons rather than losing them. Electron affinity is a measure of the energy change when an atom accepts an extra electron. It is difficult to measure directly and this has only been achieved in a few cases more often it is obtained from enthalpy cycle calculations (p. 74). 

Atomic number Element Atomic radius (g) (nm) Radius ofX ion (nm) Electron affinity (kJ mol )... 

Table 2.6 shows the electron affinities, for the addition of one electron to elements in Periods 2 and 3. Energy is evolved by many atoms when they accept electrons. In the cases in which energy is absorbed it will be noted that the new electron enters either a previously unoccupied orbital or a half-filled orbital thus in beryllium or magnesium the new electron enters the p orbital, and in nitrogen electron-pairing in the p orbitals is necessary. 

Bromine has a lower electron affinity and electrode potential than chlorine but is still a very reactive element. It combines violently with alkali metals and reacts spontaneously with phosphorus, arsenic and antimony. When heated it reacts with many other elements, including gold, but it does not attack platinum, and silver forms a protective film of silver bromide. Because of the strong oxidising properties, bromine, like fluorine and chlorine, tends to form compounds with the electropositive element in a high oxidation state. 

Table 4.4 Electron Affinities of Elements, Molecules, and Radicals...

Several portions of Section 4, Properties of Atoms, Radicals, and Bonds, have been significantly enlarged. For example, the entries under Ionization Energy of Molecular and Radical Species now number 740 and have an additional column with the enthalpy of formation of the ions. Likewise, the table on Electron Affinities of the Elements, Molecules, and Radicals now contains about 225 entries. The Table of Nuclides has material on additional radionuclides, their radiations, and the neutron capture cross sections. 

The detection limit of each element depends upon the electron affinity or ionization potential of the element itself, the chemical nature of the sample in which it is contained, and the type and intensity of the primary ion beam used in the sputtering process. 

The ground-state electronic structure of As, as with all Group 15 elements features 3 unpaired electrons ns np there is a substantial electron affinity for the acquisition of 1 electron but further additions must be effected against considerable coulombic repulsion, and the formation of As is highly endothermic. Consistent with this there are no ionic compounds containing the arsenide ion and... 

The ionization energy, electron affinity, and orbital occupancy determine the chemical behavior, or reactivity, of the elements. The uppermost (high-est-energy) occupied orbitals are called the valence orbitals the electrons occupying them are the valence electrons. An element s ionization energy, the energy required to remove an electron from a neutral atom, is related to its reactivity A low ionization energy means that the valence electron is readily removed, and the element is likely to become involved in... 

Electron affinities are difficult to measure and are known reliably for only a small fraction of the hundred or so elements. The electron affinity of fluorine is one that is known ... 

Elements with the highest electron affinities are those in Groups 16/VI and... 

Elements at the right of the p block have characteristically high electron affinities they tend to gain electrons to complete closed shells. Except for the metalloids tellurium and polonium, the members of Groups 16/VI and 17/VII are nonmetals (Fig. 1.62). They typically form molecular compounds with one another. They react with metals to form the anions in ionic compounds, and hence many of the minerals that surround us, such as limestone and granite, contain anions formed from non-metals, such as S2-, CO,2-, and S042-. Much of the metals industry is concerned with the problem of extracting metals from their combinations with nonmetals. 

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