Block (periodic table) valence electrons, and, except for helium, are only slightly less reactive. The p-block is on the right side of the periodic table and includes elements from the six columns beginning with column 13 and ending with column 18. Helium, though being in the top of group 18, is not included in the p-block.General valance configration is ns np1-6. The p-block COB This contains variety of elements and is the only block that contains all three types of elements: metals, nonmetals, and metalloids. Generally, the p-block elements are best described in terms of element type or group. P-block elements are unified
History of the periodic table History of the periodic table The periodic table is an arrangement of the chemical elements and are organized on the basis of their atomic numbers, electron configurations and recurring chemical properties. Elements are presented in order of increasing atomic number. The standard form of the table consists of a grid of elements with rows called periods and columns called groups. The history of the periodic table reflects over a century of growth in the understanding of chemical properties. The most important event in its history occurred in 1869, when the table was published by Dmitri Mendeleev, who built upon earlier