Distorted-wave calculations of the triply differential cross sections for electron-impact ionization of Li and Mg are presented for the coplanar, ${\mathrm{\ensuremath{\theta}}}_{12}$=\ensuremath{\pi} geometry in which the final-state electrons share 2 eV of excess energy equally. Our theoretical approach, described in detail elsewhere [C. Pan and A. F. Starace, Phys. Rev. A 45, 4588 (1992)], employs a partial-wave expansion of initial- and final-state wave functions, treats direct and exchange interactions of initial and final electrons with the target core, and treats the final-state interaction between the two continuum electrons by a screening potential. Li and Mg targets are found to have more complex (e,2e) angular distributions than either H or He targets, stemming in large part from significant p-wave and higher one-electron phase shifts in the former elements.