High resolution electron energy loss spectroscopy has been performed as a function of temperature (15–300 K) to determine the electronic transitions of clean and metallized Si(111) surfaces. A quantitative analysis of these EELS results is used to delineate and identify the localized and delocalized states at the Fermi level. Si(111)‐7×7 is found to have a 100 meV surface state band gap in which lies a narrow, half occupied state that determines the Fermi level. Hydrogen titration studies suggest densities of these states at ∼1.6×1013/cm2. In contrast, metal impurity stabilized Si(111)‐1×1 surfaces are not found to have these narrow states atEF. Au overlayers on Si(111)‐1×1 produce a metallic overlayer for coverages above ∼1.6×1015Au/cm2. Pd reaction with Si(111)‐1×1 forms a semimetal or semiconducting compound at coverages ≲1×1015atoms/cm2and appears to generate narrow partially occupied Si states at the interface. At higher Pd coverages a metallic silicide forms which uniformly covers the surface.