Influence of electron's kinetic energy disspation during photoelectric

[EbalOsla]

What are the properties of a metal that determine its work function? What has a greater influence on its value: the electromagnetic energy of an electron (which is going to leave metal's volume because of photoelectric emission) and the atoms of the metal or the dissipation of electron's kinetic energy in the process of THIS electron leaving the volume of the metal?

 

[tech99]

I think the heavier alkali metals, such as Potassium, have a low work function, which I imagine is due to the loose binding of the electron in the outer shell?