An analytic atomic independent particle model potential adjusted to experimental single-particle energy levels is used to generate wavefunctions for the valence and excited states of 0, F +I, Ne +2, Na +3, Mg +4 and A1 +5. Using these wavefunctions in conjunction with the Born approximation and the LS-coupling scheme, we calculate optical oscillator strengths for excitations from the ls 2 2s 2 2p4(aP2) ground state. Good agreement is obtained with experimental data. Systematic trends along the isoelectronic sequence are discussed.