For example I'm trying to get the term symbol of $(1s)^{2}(2s)^{2}(2p)^2$ . In the answers they state the following:
The combination of angular momenta $L_1$ = $L_2$ = 1$L_1 = L_2 = 1$ gives L = 2$L = 2$ (symmetric), L = 1 $L = 1$ (antisymmetric) and L = 0$L = 0$ (symmetric). This must be combined with the spin spin wave function of opposite symmetry, thus $^1D_2, ^3P_{0, 1, 2}$ and $^1S_0.$
I totally understand this, except for how they assign symmetric and antisymmetric to the angular momenta. In the previous exercise I only had L = 0$L = 0$ and they said it was symmetric and antisymmetric. So how do I know if the angular momentum is symmetric or antisymmetric?