A precise equation for the work function showing the dependence of the work function on basic metal parameters such as density, atomic mass and valence is presented in the article. Presented equation is a result of a combination of the unconventional use of Schrodinger equation and thorough analysis of experimental data related with the work function. Introduced model is applied to discuss the change of the work function due to the number of valence electrons with respect to transition metals. The values obtained directly from the equation are compared with the results obtained by other authors specializing in these issues.