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5 days ago · Recent News. gold (Au), chemical element, a dense lustrous yellow precious metal of Group 11 (Ib), Period 6, of the periodic table of the elements. Gold has several qualities that have made it exceptionally valuable throughout history.
2 days ago · List of space groups. There are 230 space groups in three dimensions, given by a number index, and a full name in Hermann–Mauguin notation, and a short name (international short symbol). The long names are given with spaces for readability. The groups each have a point group of the unit cell.
2 days ago · Gold is a chemical element with the symbol Au (from the Latin word aurum) and the atomic number 79. In its pure form, it is a bright, slightly orange-yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal, a group 11 element, and one of the noble metals.
4 days ago · In mathematics, a group is a set with an operation that satisfies the following constraints: the operation is associative and has an identity element, and every element of the set has an inverse element. Many mathematical structures are groups endowed with other properties.
2 days ago · Electrons and a compact nucleus of protons and neutrons. Atoms are the basic particles of the chemical elements. An atom consists of a nucleus of protons and generally neutrons, surrounded by an electromagnetically bound swarm of electrons. The chemical elements are distinguished from each other by the number of protons that are in their atoms.
2 days ago · Formal definition. A topological group, G, is a topological space that is also a group such that the group operation (in this case product): ⋅ : G × G → G, (x, y) ↦ xy. and the inversion map: −1 : G → G, x ↦ x−1. are continuous. [note 1] Here G × G is viewed as a topological space with the product topology.
5 days ago · Another common method of categorization recognizes nine element families: Alkali Metals: Group 1 (IA) - one valence electron. Alkaline Earth Metals: Group 2 (IIA) - two valence electrons. Transition Metals: Groups 3-12 - two valence electrons. Boron Group or Earth Metals: Group 13 (IIIA) - three valence electrons.
