Why does Cl have a higher electron affinity than Fluorine even though it's below Fluorine in the halogen group?

Electron affinity is the amount of energy released when an electron is added to an atom. Electron affinity increases from left to right in a period and decreases down the group.Chlorine is below Fluorine in the Halogen group. Yet chlorine has a higher electron affinity than fluorine.

Why?

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  • Anonymous
    1 decade ago
    Favorite Answer

    Yes, fluorine is one of the exceptions -- and the element with the highest electron affinity is chlorine (note that the most electronegative element is fluorine however).

    The reason that the electron affinity is not as high as might otherwise be predicted for fluorine is that it is an extremely small atom, and so it's electron density is very high. Adding an additional electron is therefore not quite as favorable as for an element like chlorine where the electron density is slightly lower (due to electron-electron repulsion between the added electron and the other electrons in the electron cloud).

    • Damian3 years agoReport

      Bromine and Iodine have lower effective nuclear charges on the valence electrons due to the higher energy levels.

      Chlorine is the one element with the lowest energy level (3), the greatest electrostatic pull on that energy level, and with access to the d subshell for a lower electron density.

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  • 5 years ago

    This Site Might Help You.

    RE:

    Why does Cl have a higher electron affinity than Fluorine even though it's below Fluorine in the halogen group?

    Electron affinity is the amount of energy released when an electron is added to an atom. Electron affinity increases from left to right in a period and decreases down the group.Chlorine is below Fluorine in the Halogen group. Yet chlorine has a higher electron affinity than fluorine.

    Why?

    Source(s): cl higher electron affinity fluorine 39 fluorine halogen group: https://shortly.im/AS2ay
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  • Anonymous
    6 years ago

    the electronic configuration of fluorine is 1s2 2s2 2p5 for this reason it has no such d subshell that chlorine contains so its eletron density is higher now if it accepts one electron therefore electron electron repulsion would be higher,where as on the other hand chlorine has an electronic con figuration 1s2 2s2 2p6 3s2 3p5 and the 3d subshell is empty so it has a capability to accommodate more electrons and the electron electron repulsion would be less compared to fluorine as a result of which more electrons would be accepted by chlorine for this reason chlorine has more electron affinity than fluorine.

    NOW FROM THOSE PREVIOUS EXPLANATIONS MY QUESTION IS THAT IF IT DEPENDS ON SIZE OF FLUORINE THEN BROMINE AS WELL AS IODINE HAS A LARGER SIZE THAN FLUORINE THEN WHY THEY DON'T HAVE AN ELECTRON AFFINITY MORE THAN THAT OF FLUORINE?

    FROM :MEGHAMITRA DUTTA

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  • 1 decade ago

    Because of the proximity of the electrons in fluorine.

    Because of its small size, the fluorine atom exerts a significant pull on its electrons. However, its small size also causes the electrons to approach each other very closely, meaning they start to repel each other due to their like charge. To insert another electron in the highly repelling environment of fluorine would take a certain amount of energy.

    Chlorine is larger in size. Because of this, it is less reactive, since the nucleus does not exert such a great pull on electrons. However, inserting an electron in a shell where there is much more space will not take as much energy, because the repulsion to be overcome is lower. This means that it is more energy efficient than for the fluorine atom.

    Hence, chlorine has a higher electron affinity than fluorine.

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  • 4 years ago

    For the best answers, search on this site https://shorturl.im/ax8e2

    Chlorine is further down on the column in the periodic table. Chlorine has a larger electron cloud than Fluorine.

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  • 4 years ago

    Fluorine has small size. It also has high interelectronic repulsions in relatively small 2p orbitals. Hence incoming electron experiences less attraction from the nucleus... Thats why... :)

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  • Anonymous
    1 decade ago

    Flourine is the most electronegative: has the highest electron affinity.

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