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A chemical element, often simply called an element, is a type of atom which has a specific number of protons in its atomic nucleus (i.e., a specific atomic number, or Z). [ 1 ] The definitive visualisation of all 118 elements is the periodic table of the elements , whose history along the principles of the periodic law was one of the founding ...
Each chemical element has a unique atomic number (Z— for "Zahl", German for "number") representing the number of protons in its nucleus. [4] Each distinct atomic number therefore corresponds to a class of atom: these classes are called the chemical elements. [5] The chemical elements are what the periodic table classifies and organizes.
Hydrazine is an inorganic compound with the chemical formula N 2 H 4.It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour.Hydrazine is highly hazardous unless handled in solution as, for example, hydrazine hydrate (N 2 H 4 ·xH 2 O).
Each element is detailed with the name, symbol and number of electrons in each shell. The colour scheme is designed to match that used : 21:16, 1 April 2007: 4,213 × 2,980 (4.57 MB) GregRobson == Summary == * '''Description:''' Diagram showing the periodic table of elements in the form of their electron shells.
This is a list of chemical elements and their atomic properties, ordered by atomic number (Z). Since valence electrons are not clearly defined for the d-block and f-block elements, there not being a clear point at which further ionisation becomes unprofitable, a purely formal definition as number of electrons in the outermost shell has been used.
There are currently seven complete periods in the periodic table, comprising the 118 known elements. Any new elements will be placed into an eighth period; see extended periodic table. The elements are colour-coded below by their block: red for the s-block, yellow for the p-block, blue for the d-block, and green for the f-block.
Hydrazines (R 2 N−NR 2) are a class of chemical compounds with two nitrogen atoms linked via a covalent bond and which carry from one up to four alkyl or aryl substituents. . Hydrazines can be considered as derivatives of the inorganic hydrazine (H 2 N−NH 2), in which one or more hydrogen atoms have been replaced by hydrocarbon grou
Here [Ne] refers to the core electrons which are the same as for the element neon (Ne), the last noble gas before phosphorus in the periodic table. The valence electrons (here 3s 2 3p 3) are written explicitly for all atoms. Electron configurations of elements beyond hassium (element 108) have never been measured; predictions are used below.