Period 2 element Period 2 element A period 2 element is one of the chemical elements in the second row (or period) of the periodic table of the chemical elements. The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behavior of the elements as their atomic number increases; a new row is started when chemical behavior begins to repeat, creating columns of elements with similar properties. The second period contains the elements lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine, and neon. This situation can be explained by modern theories of atomic structure. In a quantum mechanical
Mendeleev's predicted elements a systematic element name based on the atomic number of the element as the provisional name, instead of being based on its position in the periodic table as these prefixes require. The four predicted elements lighter than the rare-earth elements, "eka-boron" ("Eb"), "eka-aluminium" ("Ea" or "El",), "eka-manganese" ("Em"), and "eka-silicon" ("Es"), proved to be good predictors of the properties of scandium, gallium, technetium, and germanium respectively, which fill the spot in the periodic table assigned by Mendeleev. The names were written by Mendeleev as экаборъ, экаалюминій, экамарганецъ, and экасилицій respectively, following the pre-1917 Russian orthography. Initial versions of the periodic