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Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at seventh in total abundance in the Milky Way and the Solar System. At standard temperature and pressure, two atoms of the element bond to form N 2, a colourless and odourless diatomic ...
This list is sorted by boiling point of gases in ascending order, but can be sorted on different values. "sub" and "triple" refer to the sublimation point and the triple point, which are given in the case of a substance that sublimes at 1 atm; "dec" refers to decomposition. "~" means approximately.
The solid form has a hexagonal crystalline structure and is soft and easily crushed. Hydrogen is an insulator in all of its forms. It has a high ionisation energy (1312.0 kJ/mol), moderate electron affinity (73 kJ/mol), and moderate electronegativity (2.2). Hydrogen is a poor oxidising agent (H 2 + 2e − → 2H – = –2.25 V at pH 0). Its ...
β-N (none) Hexagonal: P6 3 /mmc (No. 194) 4: α-Po: A h: Cubic: Pm 3 m (No. 221) 1: 6 nearest neighbours: simple cubic lattice. The atoms in the unit cell are at the corner of a cube. γ-O (none) Cubic: Pm 3 n (No. 223) 16: Closely related to the β-W structure, except with a diatomic oxygen molecule in place of each tungsten atom. The ...
In 1828 and 1859, the French chemist Dumas classified nonmetals as (1) hydrogen; (2) fluorine to iodine; (3) oxygen to sulfur; (4) nitrogen to arsenic; and (5) carbon, boron and silicon, [213] thereby anticipating the vertical groupings of Mendeleev's 1871 periodic table.
Nevertheless, nitrogen gas does react with the alkali metal lithium to form compound lithium nitride (Li 3 N), even under ordinary conditions. Under high pressures and temperatures and with the right catalysts, nitrogen becomes more reactive; the Haber process uses such conditions to produce ammonia from atmospheric nitrogen.
2 according to the 3-center-4-electron bond model. Noble gas compounds such as xenon difluoride (XeF 2) are considered to be hypervalent because they violate the octet rule. Bonding in such compounds can be explained using a three-center four-electron bond model. [66] [67] This model, first proposed in 1951, considers bonding of three collinear ...
Periodic table of the chemical elements showing the most or more commonly named sets of elements (in periodic tables), and a traditional dividing line between metals and nonmetals. The f-block actually fits between groups 2 and 3 ; it is usually shown at the foot of the table to save horizontal space.