$Ne_2$ has 20 electrons: $\sigma1s^2\,\sigma^*1s^2\,\sigma2s^2\,\sigma^*2s^2\,\sigma2p_z^2\,\pi2p_x^2=\pi2p_y^2\,\pi^*2p_x^2=\pi^*2p_y^2\,\sigma^*2p_z^2$. The highest occupied molecular orbital (HOMO) is $\sigma^*2p_z$.