Electron affinities

Example of IE1 the Magnesium: Mg(g) -> Mg+(g) + e- I1 = 738 kJ/mol

IE1 stands for the first ionization energy: the power the atom requires to expel the an initial electron from its orbital. Similarly, the 2nd ionization energy, will certainly be the power needed come expel the 2nd electron.

Mg+(g) -> Mg2+(g) + e- I2 = 1,451 kJ/mol

However, IE2 that Magnesium will be bigger than the of IE1 due to the fact that it is not energetically favorable to separate an electron indigenous a positively charged ion.

The general pattern the the ionization energy as they are in regard come the duration table is the the ie increases throughout a period, and decreases down a group. Since it requires much more energy to eliminate an electron native a stable atom, the noble gases are usually linked with the greatest IE1. Since their valence shells are currently filled and stablized, castle will call for much much more energy come disrupt that stability. The an initial electron the is expelled is the most loosely organized to the atom.

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On the various other hand, the team 1 elements are usually connected with the shortest IE1. Since only one electron occupies the valence covering of this atoms, it will certainly be an ext energetically favorable because that them to shed the electron in order to attain a full orbital shell.

However, there are few exceptions. The IE1 decreases once crossing from facet in team 15 come the element in team 16. The team 15 has actually half-filled electronic configuration ns2 np3. This type of configuration is really stable; it’s hard to eliminate electron native valence shell. Therefore, facet in team 15 requires higher value the IE1 than team 16. Another exception is the going from be (group 2) to B (group 13), the IE1 decreases because Be has actually the filled shell 2s2 i m sorry is much more stable 보다 the electronic configuration the B 2s2 2p1. Hence, Be will require much more IE1 than B. Similarly, the IE1 decreases when going from facets in group 12 to group 13


Electron Affinities

Electron affinity, regularly abbreviated together EA, is the energy released when an electron is included to a valence covering of the atom.

F(g) + e- -> F-(g) EA = -328 kJ/mol

Atoms like the noble gases will not gain an electron due to the fact that they are currently in their many stable state with a complete shell. Atoms prefer F will many likely gain an electron due to the fact that when a free electron is added to the outer shell that fluorine, it will have derived a full shell. Generally, atoms increasing throughout a period will rise in EA also.

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Exothermic vs endothermic process

O(g) + e- -> O-(g) EA1= -141.0 kJ/mol

O-(g) + e- -> O2-(g) EA2 = +744kJ/mol

When an electron is included to an atom, the energy change is exothermic due to the fact that of the attraction of the electron to the nucleus. However, in the instance of EA2 whereby the electron is added to one anion, the repulsion between the anion and this newly included electron will certainly overwhelm the attraction the the electron to the nucleus. Therefore, this procedure will be endothermic, as opposed come EA1.


Periodic Trend

The basic trend of IE and also EA along a regular table.

IE and also EA.jpgis ionization energy endothermic or exothermic