* Electron Configuration: Alkali metals have only one valence electron (in the outermost shell), which they readily lose to achieve a stable octet. This makes them highly reactive. Transition metals, on the other hand, have multiple valence electrons and can lose different numbers of electrons, making their reactivity more complex.

* Electropositivity: Alkali metals are highly electropositive, meaning they have a strong tendency to lose electrons and form positive ions. This makes them readily react with other elements, especially nonmetals. Transition metals are less electropositive and less readily form ions.

* Ionization Energy: Alkali metals have lower ionization energies compared to transition metals. This means it takes less energy to remove an electron from an alkali metal atom, making them more reactive.

Exceptions:

While the general trend holds true, there are some exceptions. For example, some transition metals like gold and platinum are very unreactive due to their high ionization energies and the presence of filled d-orbitals.

In summary:

While there are some exceptions, alkali metals are generally more reactive than transition metals because of their electron configurations, electropositivity, and lower ionization energies.