I understand that electron affinity is generally exothermic(groups 16 and 17). But, alkali metals are reluctant to gain an electron because losing electrons is beneficial for them. So, the electron gain enthalpy is termed endothermic (source: Chem libretexts) for alkali metals because it is hard to add an electron to their atoms and you need to invest energy. If it is endothermic, the electron affinity values must be positive, but they are still negative. Why? Why do the values still represent the release of energy?

In the image, the EA values of alkali metals are still negative, not positive. But in the description, it says that the process of adding an electron to alkali metals associates with the absorption of energy (endothermic- positive)

Source https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Physical_Properties_of_Matter/Atomic_and_Molecular_Properties/Electron_Affinity

alkali metals electorn affinities

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    $\begingroup$ That means you should stick to the source with electron affinity values not some "Chem libretexts". chemistry.stackexchange.com/questions/51400/… $\endgroup$
    – Mithoron
    Oct 25, 2022 at 14:00
  • $\begingroup$ Wow that's terrible. It completely contradicts the rest of the content and even the values listed below the text, in the example. The electron affinities are not endothermic in those cases. It might be a matter of emphasis however. Maybe it is meant that among metals there is a decreased affinity. May be worth contacting the authors. $\endgroup$
    – Buck Thorn
    Oct 25, 2022 at 17:18


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