The schnitzel turned to leather in my mouth, the beer seemed tepid; I left the Emmenthaler untasted. Reginald in Russia Saki. Fernando was a man who had almost as little to say as had schnitzel. The Khaki Boys at Camp Sterling Josephine Chase.
The inner shells of an atomâs electrons are full and stable. For the most part, they contribute little to the way the atom reacts. The largest factor in how an atom reacts is the makeup of its outer shell electrons. The periodic table naturally groups together elements with similar outer shells (Transition metals, halogens, etc.).
Today, the periodic table organizes the elements in horizontal rows, or periods, by order of increasing atomic number, which equals the number of protons in the atomic nucleus of each element. The elements are also organized in vertical columns, or groups, based on similar physical characteristics and chemical behavior. This arrangement developed side by side with atomic theory over about 200 years, and it continues to evolve as new elements are discovered.