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Lead
Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleable, and also has a relatively low melting point. When freshly cut, lead is a shiny gray with a hint of blue. It tarnishes to a dull gray color when exposed to air. Lead has the highest atomic number of any stable nuclide, stable element and three of its isotopes are endpoints of major nuclear decay chains of heavier elements. Lead is a relatively unreactive post-transition metal. Its weak metallic character is illustrated by its Amphoterism, amphoteric nature; lead and lead oxides react with acids and base (chemistry), bases, and it tends to form covalent bonds. Lead compounds, Compounds of lead are usually found in the +2 oxidation state rather than the +4 state common with lighter members of the carbon group. Exceptions are mostly limited ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Group
The carbon group is a group (periodic table), periodic table group consisting of carbon (C), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), and flerovium (Fl). It lies within the p-block. In modern International Union of Pure and Applied Chemistry, IUPAC notation, it is called group 14. In the field of Semiconductor#Physics of semiconductors, semiconductor physics, it is still universally called group IV. The group is also known as the tetrels (from the Greek word ''tetra'', which means four), stemming from the Roman numeral IV in the group name, or (not coincidentally) from the fact that these elements have four valence electrons (see below). They are also known as the crystallogens or adamantogens. Characteristics Chemical Like other groups, the members of this family show patterns in electron configuration, especially in the outermost shells, resulting in trends in chemical behavior: Each of the chemical element, elements in this group has 4 electrons in its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead Compounds
Compounds of lead exist with lead in two main oxidation states: +2 and +4. The former is more common. Inorganic lead(IV) Compound (chemistry), compounds are typically strong oxidants or exist only in highly acidic solutions. Chemistry Various oxidized forms of lead are easily reduced to the metal. An example is heating PbO with mild organic reducing agents such as glucose. The mixture of the oxide and the sulfide heated together will also form the metal. : 2 PbO + PbS → 3 Pb + SO2 Metallic lead is attacked (oxidized) only superficially by air, forming a thin layer of lead oxide that protects it from further oxidation. The metal is not attacked by sulfuric acid, sulfuric or hydrochloric acid, hydrochloric acids. It dissolves in nitric acid with the evolution of nitric oxide gas to form dissolved lead(II) nitrate, Pb(NO3)2. : 3 Pb + 8 H+ + 8 → 3 Pb2+ + 6 + 2 NO + 4 H2O When heated with nitrates of alkali metals, metallic lead oxidizes to form lead(II) oxide, PbO (also k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decay Chain
In nuclear science a decay chain refers to the predictable series of radioactive disintegrations undergone by the nuclei of certain unstable chemical elements. Radioactive isotopes do not usually decay directly to stable isotopes, but rather into another radioisotope. The isotope produced by this radioactive emission then decays into another, often radioactive isotope. This chain of decays always terminates in a stable isotope, whose nucleus no longer has the surplus of energy necessary to produce another emission of radiation. Such stable isotopes may be said to have reached their '' ground states''. The stages or steps in a decay chain are referred to by their relationship to previous or subsequent stages. Hence, a ''parent isotope'' is one that undergoes decay to form a ''daughter isotope''. For example element 92, uranium, has an isotope with 144 neutrons ( 236U) and it decays into an isotope of element 90, thorium, with 142 neutrons ( 232Th). The daughter isotope may be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heavy Metal (elements)
upright=1.2, Crystals of lead.html" ;"title="osmium, a heavy metal nearly twice as dense as lead">osmium, a heavy metal nearly twice as dense as lead Heavy metals is a controversial and ambiguous term for metallic elements with relatively high density, densities, atomic weights, or atomic numbers. The criteria used, and whether metalloids are included, vary depending on the author and context and it has been argued that the term "heavy metal" should be avoided. A heavy metal may be defined on the basis of density, atomic number or chemical behaviour. More specific definitions have been published, none of which have been widely accepted. The definitions surveyed in this article encompass up to 96 out of the 118 known chemical elements; only mercury, lead and bismuth meet all of them. Despite this lack of agreement, the term (plural or singular) is widely used in science. A density of more than 5 g/cm3 is sometimes quoted as a commonly used criterion and is used in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galena
Galena, also called lead glance, is the natural mineral form of lead(II) sulfide (PbS). It is the most important ore of lead and an important source of silver. Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the Cubic (crystal system), cubic crystal system often showing octahedral forms. It is often associated with the minerals sphalerite, calcite and fluorite. As a pure specimen held in the hand, under standard temperature and pressure, galena is insoluble in water and so is almost non-toxic. Handling galena under these specific conditions (such as in a museum or as part of geology instruction) poses practically no risk; however, as lead(II) sulfide is reasonably reactive in a variety of environments, it can be highly toxic if swallowed or inhaled, particularly under prolonged or repeated exposure. Occurrence Galena is the main ore of lead, used since ancient times, since lead can be smelted from galena in an ordinary wood fire. G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead Oxide
Lead oxides are a group of inorganic compounds with formulas including lead (Pb) and oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ... (O). Common lead oxides include: * Lead(II) oxide, PbO, litharge (red), massicot (yellow) * Lead tetroxide or ''red lead'', , minium, which is a lead (II,IV) oxide and may be thought of as lead(II) orthoplumbate(IV) , vivid orange crystals * Lead dioxide (lead(IV) oxide), , dark-brown or black powder Less common lead oxides are: * Lead sesquioxide, , which is a lead (II,IV) oxide as well ( lead(II) metaplumbate(IV) ), reddish yellow * , monoclinic, dark-brown or black crystals * The so-called ''black lead oxide'', which is a mixture of PbO and fine-powdered Pb metal and used in the production of lead–acid batteries. {{Authority ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Post-transition Metal
The metallic elements in the periodic table located between the transition metals to their left and the chemically weak nonmetallic metalloids to their right have received many names in the literature, such as post-transition metals, poor metals, other metals, p-block metals, basic metals, and chemically weak metals. The most common name, ''post-transition metals'', is generally used in this article. Physically, these metals are soft (or brittle), have poor mechanical strength, and usually have melting points lower than those of the transition metals. Being close to the metal-nonmetal border, their crystalline structures tend to show covalent or directional bonding effects, having generally greater complexity or fewer nearest neighbours than other metallic elements. Chemically, they are characterised—to varying degrees—by covalent bonding tendencies, acid-base amphoterism and the formation of anionic species such as aluminates, stannates, and bismuthates (in the cas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stable Nuclide
Stable nuclides are isotopes of a chemical element whose nucleons are in a configuration that does not permit them the surplus energy required to produce a radioactive emission. The nuclei of such isotopes are not radioactive and unlike radionuclides do not spontaneously undergo radioactive decay. When these nuclides are referred to in relation to specific elements they are usually called that element's stable isotopes. The 80 elements with one or more stable isotopes comprise a total of 251 nuclides that have not been shown to decay using current equipment. Of these 80 elements, 26 have only one stable isotope and are called monoisotopic. The other 56 have more than one stable isotope. Tin has ten stable isotopes, the largest number of any element. Definition of stability, and naturally occurring nuclides Most naturally occurring nuclides are stable (about 251; see list at the end of this article), and about 35 more (total of 286) are known to be radioactive with long eno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metals Of Antiquity
The metals of antiquity are the seven metals which humans had identified and found use for in prehistoric times in Africa, Europe and throughout Asia: gold, silver, copper, tin, lead, iron, and mercury (element), mercury. Zinc, arsenic, and antimony were also known during antiquity, but they were not recognised as distinct metals until later. A special case is platinum; it was known to native South Americans around the time Europe was going through classical antiquity, but was unknown to Europeans until the 18th century. Thus, at most eleven elemental metals and metalloids were known by the end of antiquity; this contrasts greatly with the situation today, with over 90 elemental metals known. Bismuth only began to be recognised as distinct around 1500 by the European and Incan civilisations. The first elemental metal with a clearly identifiable discoverer is cobalt, discovered in 1735 by Georg Brandt, by which time the Scientific Revolution was in full swing. (Even then, cobalt m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amphoterism
In chemistry, an amphoteric compound () is a molecule or ion that can react both as an acid and as a base. What exactly this can mean depends on which definitions of acids and bases are being used. Etymology and terminology Amphoteric is derived from the Greek word () meaning "both". Related words in acid-base chemistry are amphichromatic and amphichroic, both describing substances such as acid-base indicators which give one colour on reaction with an acid and another colour on reaction with a base. Amphiprotism Amphiprotism is exhibited by compounds with both Brønsted acidic and basic properties. A prime example is H2O. Amphiprotic molecules can either donate or accept a proton (). Amino acids (and proteins) are amphiprotic molecules because of their amine () and carboxylic acid () groups. Ampholytes Ampholytes are zwitterions ‒ molecules or ions that contain both acidic and basic functional groups. Amino acids have both a basic group and an acidic group . Of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Movable Type
Movable type (US English; moveable type in British English) is the system and technology of printing and typography that uses movable Sort (typesetting), components to reproduce the elements of a document (usually individual alphanumeric characters or punctuation marks) usually on the medium of paper. Overview The world's first movable type printing technology for paper books was made of porcelain materials and was invented around 1040 AD in China during the Northern Song dynasty by the inventor Bi Sheng (990–1051). The earliest printed paper money with movable metal type to print the identifying Banknote seal (China), code of the money was made in 1161 during the Song dynasty. In 1193, a book in the Song dynasty documented how to use the copper movable type. The oldest extant book printed with movable metal type, Jikji, was printed in Korea in 1377 during the Goryeo dynasty. The spread of both movable-type systems was, to some degree, limited to primarily East Asia. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Symbol
Chemical symbols are the abbreviations used in chemistry, mainly for chemical elements; but also for functional groups, chemical compounds, and other entities. Element symbols for chemical elements, also known as atomic symbols, normally consist of one or two letters from the Latin alphabet and are written with the first letter capitalised. History Earlier symbols for chemical elements stem from classical Latin and Greek language, Greek words. For some elements, this is because the material was known in ancient times, while for others, the name is a more recent invention. For example, Pb is the symbol for lead (''plumbum'' in Latin); Hg is the symbol for mercury (element), mercury (''hydrargyrum'' in Greek); and He is the symbol for helium (a Neo-Latin name) because helium was not known in ancient Roman times. Some symbols come from other sources, like W for tungsten (''Wolfram'' in German) which was not known in Roman times. A three-letter Systematic element name, temporary sym ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
