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
Atomic number ), the single element from which Rutherford made his guess). Nevertheless, in spite of Rutherford's estimation that gold had a central charge of about 100 (but was element on the periodic table), a month after Rutherford's paper appeared, Antonius van den Broek first formally suggested that the central charge and number of electrons in an atom was "exactly" equal to its place in the periodic table (also known as element number, atomic number, and symbolized "Z"). This proved eventually to be the case. The experimental position improved dramatically after research by Henry Moseley in 1913. Moseley, after discussions with Bohr