similar to a group (halogen family) elements. Because it is a special case, we shall place hydrogen separately at the top of the Periodic Table as shown in Fig. . and Fig.
. . We will briefly discuss the salient features of the four types of elements marked in the Periodic Table. More about these elements Thus it can be seen that the properties of an element have periodic dependence upon its atomic number and not on relative atomic mass.
. ELECTRONIC CONFIGURATIONS A N D T Y P E S O F E L E M E N T S : s-, p-, d-, f- BLOCKS The aufbau (build up) principle and the electronic configuration of atoms provide will be discussed later. During the description of their features certain terminology has been used which has been classified in section . .
. . The s -Block Elements The elements of Group (alkali metals) and Group (alkaline earth metals) which have ns and ns outermost electronic configuration belong to the s- Block Elements . They are all Atomic number Symbol Electronic configuration K Rb Cs Fr s s (or) [He] s s s p s (or) [Ne] s s s p s p s (or) [Ar] s s s p s p d s p s (or) [Kr] s s s p s p d s p d s p s (or) [Xe] s [Rn] s Nh Mc Ts Og Fig.
. The types of elements in the Periodic Table based on the orbitals that are being filled. Also shown is the broad division of elements into METALS (