[besjbo]

Why does it seem as if it's commonly understood that a higher electronegativity means reactivity is higher, but the relationship seems exactly opposite when looking at the metal reactivity series?

When considering the metals Cu, Zn, Mg, Na, Sn, Ag, and Cd, sodium (EN = 0.9) is most reactive. Mg (EN = 1.2) is next. Least reactive is Ag (EN = 1.9). This relationship seems pretty consistent for all the metals. As you go down the reactivity series (to less reactive metals), electronegativity increases. However, almost all sources indicate that more electronegative metals are more reactive.

Why the discrepancy? I feel like I'm overlooking something very fundamental, but I need to understand what.

Thank you for your help.

[XGen]

I have a feeling that reactivity increases with an increase in electronegativity for non-metals, and the opposite occurs with metals. This is because of the different ways they react.

[besjbo]

I'll be honest, I haven't seen it written that clearly anywhere I've looked. But if you're right, things would make more sense.

[Borek]

Electronegativity changes from 0.8 for alkali metals to 4 for fluorine. Middle of the scale usually means low reactivity, the higher or the lower you get, the higher the reactivity. But it is just a very approximate rule of thumb, that easily fails (and sometimes it fails in an epic way - Kr has electronegativity of 3, higher than bromine!).

Just don't use electronegativity to predict reactivity and you will be on the safe side.

[ramboacid]

I haven't seen that rule written anywhere either, though as nonmetals generally react by forming negative anions, higher electronegativities for nonmetals would suggest that they would more readily form anions than nonmetals with smaller electronegativities. Likewise, metals generally react by forming positive cations, and thus it would be to a metal's advantage in terms of reactivity to easily lose its electrons, hence suggesting a smaller electronegativity.