Periodic Table and the Electron Configuration

PERIODIC TABLE AND THE ELECTRON CONFIGURATION

            The atomic number also tells us the number of electron of elements. The electron configuration explains how physical and chemical properties of elements recur in the periodic table.

   

                The electron configuration of elements in Groups 1A and 2A ends with s-sublevel, thus, called s-block while the elements in Groups 3A to 8A ends with p-sublevel, thus called the p-block. The elements from Groups 1A to 7A with incomplete s- or p-sublevels of the highest principal quantum number are collectively called as the Representative Elements. Elements in Group 8A have completely filled s- or p-sublevel, and are not classified as representative elements. These elements are called the Noble Gases. The electron configuration of elements between s- and p-blocks ends with d-sublevels, thus are called Transition Elements. Elements in Group 2B are sometimes called post-transition elements because their d-sublevels are completely filled. Elements with electron configurations ending with f sublevel are called Inner Transition Elements and are grouped in the f-block.

                Comparison between the Representative and Transition Elements are as follows:

Representative Elements	Transition Elements
Constant oxidation state Ions are usually colorless Ions are diamagnetic	Variable oxidation states Often form colored ions Ions are paramagnetic