Block (periodic table) side of the periodic table and includes elements from the first two columns, the alkali metals (group 1) and alkaline earth metals (group 2), plus hydrogen and helium. Helium can be placed in the second group of s block as well as the 18th group of p-block, but most scientists consider it to rest at the top of group 18 i.e. above neon (atomic number 10) as it has many properties similar to the group 18 elements.General valance configration is ns1-2 Most s-block elements are highly reactive metals due to the ease with which their outer s-orbital electrons interact to
Periodic table include a two-element s-block for elements 119 and 120, a new g-block for the next 18 elements, and 30 additional elements continuing the current f-, d-, and p-blocks, culminating in element 168, the next noble gas. More recently, physicists such as Pekka Pyykkö have theorized that these additional elements do not follow the Madelung rule, which predicts how electron shells are filled and thus affects the appearance of the present periodic table. There are currently several competing theoretical models for the placement of the elements of atomic number less than or equal to 172. In all of these it is