Recent advances in coupled-cluster methods for the treatment of electron-correlation effects have made possible the computation of IPs and EAs of atoms with up to 10 electrons with a mean absolute deviation of 0.35 meV. To obtain this accuracy, not only the effect of double excitations must be computed in the limit of a complete basis set by means of Slater-type geminals, but also connected triple, quadruple, and quintuple excitations, spin-orbit and scalar relativistic effects, and diagonal Born-Oppenheimer corrections must be accounted for.