Cesium — φ = 2.10 eV Potassium — φ = 2.30 eV Sodium — φ = 2.36 eV Lithium — φ = 2.90 eV Aluminum — φ = 4.08 eV Zinc — φ = 4.31 eV Copper — φ = 4.65 eV Silver — φ = 4.74 eV Gold — φ = 5.10 eV Platinum — φ = 5.65 eV