A model calculation using the Hubbard model in conjunction with the chemisorption theory based on the Hartree-Fock approximation has been carried out to study the ground-state configuration of Pt (110) surface atoms with the least coordination number. It is found that for these atoms the number of 5d holes is larger than 2 and the 6s orbital is almost filled in contrast to the common belief that their configurations lie between that of a free atom and the bulk of crystal. The results also suggest a trend that the d electron transfer from the corresponding surface atom to the bulk is maximum in group VIII metals for a given transition series.