Maclaurin expansions of the spherically averaged electron-pair intracule (relative motion) (h) over bar(nu) and extracule (center-of-mass motion) (d) over bar( P) densities in momentum space are studied for multi-determinant wave functions. The densities (h) over bar(nu) and (d) over bar(P) are expanded by even powers of nu and P, respectively. Accurate Hartree-Fock values of the derivatives (h) over bar((2m))(0) and (d) over bar((2m))(0) (m = 0-3) are determined for the 53 atoms from He to Xe in their ground states. The signs of the second derivatives are in agreement with the modality of (h) over bar(nu) and (d) over bar(P) reported in the literature, and the array of the signs of the successive derivatives is found to be intimately related with the valence electron configuration.