Elements in the periodic table are arranged systematically that we can determine their identity based on their positions. One of which is the identification of their orbital group. There are four kinds of groups based on where their last electron is sitting: s, p, d and f groups.
The s group are elements with valence electrons located in the s orbitals. They are alkali (group I) and the alkali earth metals (group II).
The p group are elements on the right side of the periodic table. Most of the non-metal elements are located in this group starting at Boron group (group 13) to noble gasses (group 18).
The d group are the transition metals that start from the Scandium group (group III) to the Zinc group (group 12).
The f group are the inner transition metals which are subdivided into Actinoids (element 57-71) and the Lanthanoids (89-103). They are commonly written below the d group.
Group I&II = S orbital (with the exception of Helium which is part of group 18)
Group 3 - 12 (Transition metals) = D orbital
Group 13 - 18 = P orbital
2 bottom rows (Rare earth metals) = F orbital