The term is a particular energy state and term symbol is a label to energy state. The importance of these term symbols has been emphasized in connection with the spectral and magnetic properties of complexes and metal free ions and also provide information about the energy of atomic electrons in orbital’s and total spin, total orbital and grand total momenta of whole atom and electronic configuration. Russell-Saunders (L-S) coupling and j-j coupling schemes are important schemes for determination of terms and term symbols of the atoms and ions of inner transition elements in which electrons are filled in a f sub-shell with azimuthal quantum number 3. The determination of terms and term symbols for fn configuration is very difficult work since there are seven orbital’s in f-sub shell which give large number of microstates. In this proposed work computation is done for calculating all possible terms and term symbols regarding for f3 and f11 configurations without any long tabulation with mental exercise and a comparative study was carried out between the f3 and f11 terms and term symbols. The possible microstates and spectroscopic terms calculated for f3 and f11 configuration (ions M+3) are 364 and 17. These terms are split up into quartets (5) and doublets (12). The ground state term for f3 & f11 is 4I.