Main-group element Main-group element In chemistry and atomic physics, the main group is the group of elements whose lightest members are represented by helium, lithium, beryllium, boron, carbon, nitrogen, oxygen, and fluorine as arranged in the periodic table of the elements. The main group includes the elements (except hydrogen, which is sometimes not included) in groups 1 and 2 (s-block), and groups 13 to 18 (p-block). The s-block elements are primarily characterised by one main oxidation state, and the p-block elements, when they have multiple oxidation states, often have common oxidation states separated by two units. Main-group elements (with some of the
What Is History? and were instead products of their own places and times, which in turn decided what "facts of the past" they determined into "facts of history". British historian Richard J. Evans said "What Is History?" caused a revolution in British historiography in the 1960s. Australian historian Keith Windschuttle, a critic of Carr, said "What Is History?" is one of the most influential books written about historiography, and that very few historians working in the English language since the 1960s had not read it. What Is History? What Is History? is a study that was written by the English historian E. H.