In the field of inorganic chemistry, term symbols regarding to fn configuration is to be discovered. A little work has been done in this field till now. The importance of the term symbols has been emphasized in connection with the spectral and magnetic properties of complexes, metal atoms and free ions. Russell-Saunders (L-S) coupling scheme is an important scheme 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. In this proposed work, computation is done for calculating all possible terms for f3 configurations without any long tabulation with mental exercise. Atomic spectra have provided a wealth of information about the energy of atomic orbital to meet out the problem of distributing the electrons in them. In recent years, a great interest is developed in the field of lanthanide and actinide. The determination of terms and term symbols for fn configuration is a very difficult work. Since there are seven orbital’s in f-sub shell, which give large number of microstates. The possible combinations (microstates) of orbital and spin for fn configuration (ions M3+) are enormously large viz. 14 for f1/f13, 91 for f2 /f12, 364 for f3/f11, 1001 for f4/f10, 2002 for f5/f9, 3003 for f6/f8 and 3432 for f7, respectively. Due to the bulk number of microstates and cumbersome process of their derivation, it is not given attention in literature. Present work includes information and computation of terms about f3 configuration.