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
Extended periodic table with atomic numbers above 82 (after lead) have stable isotopes. Nevertheless, because of reasons not very well understood yet, there is a slight increased nuclear stability around atomic numbers 110–114, which leads to the appearance of what is known in nuclear physics as the "island of stability". This concept, proposed by University of California professor Glenn Seaborg, explains why superheavy elements last longer than predicted. Calculations according to the Hartree–Fock–Bogoliubov method using the non-relativistic Skyrme interaction have proposed "Z" = 126 as a closed proton shell. In this region of the periodic table, "N" = 184, "N" = 196, and