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 neutron drip lines and stability toward alpha decay and spontaneous fission. One calculation by Y. Gambhir et al., analyzing nuclear binding energy and stability in various decay channels, suggests a limit to the existence of bound nuclei at "Z" = 146. Some, such as Walter Greiner, predicted that there may not be an end to the periodic table. Other predictions of an end to the periodic table include "Z" = 128 (John Emsley) and "Z" = 155 (Albert Khazan). It is a "folk legend" among physicists that Richard Feynman suggested that neutral atoms could not exist for atomic numbers greater