Model potentials for zinc, indium, thallium, lead, cadmium and mercury are constructed using an adaptation of Shaw's energy-dependent formalism which allows the effect of high d-core states to be included. In the case of mercury this leads to a striking change in the shape of the screened form factor. Numerical calculations of the thermopower in liquid zinc, indium, thallium and mercury are in better agreement with experiment than previous calculations which did not include the energy-dependent term. Calculations of the resistivity of alloys of mercury with indium, thallium, zinc and lead are presented. These show a sharp decrease of the resistivity on alloying which is in reasonable agreement with the experimental results.