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List of chemical elements. 118 chemical elements have been identified and named officially by IUPAC. 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]
This is a list of chemical elements and their atomic properties, ordered by Atomic number.. 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.
The periodic table is a tabular arrangement of the chemical elements, organized by their atomic number, electron configuration, and chemical properties. It is a useful tool for understanding the patterns and trends of the elements and their interactions. Learn more about the history, structure, and significance of the periodic table on Wikipedia.
An atom consists of a small, heavy nucleus surrounded by a relatively large, light cloud of electrons. An atomic nucleus consists of 1 or more protons and 0 or more neutrons. Protons and neutrons are, in turn, made of quarks. Each type of atom corresponds to a specific chemical element. To date, 118 elements have been discovered or created.
The atomic mass ( ma or m) is the mass of an atom. Although the SI unit of mass is the kilogram (symbol: kg), atomic mass is often expressed in the non-SI unit dalton (symbol: Da) – equivalently, unified atomic mass unit (u). 1 Da is defined as 1⁄12 of the mass of a free carbon-12 atom at rest in its ground state. [ 1]
Near misses. This list includes substances that boil just above standard condition temperatures. Numbers are boiling temperatures in °C. 1,1,2,2,3-Pentafluoropropane 25–26 °C [ 151][ 3] Dimethoxyborane 25.9 °C. 1,4-Pentadiene 25.9 °C. 2-Bromo-1,1,1-trifluoroethane 26 °C. 1,2-Difluoroethane 26 °C. Hydrogen cyanide 26 °C.
A list of current, dated, as well as proposed and historical signs and symbols is included here with its signification. Also given is each element's atomic number, atomic weight, or the atomic mass of the most stable isotope, group and period numbers on the periodic table, and etymology of the symbol.
Element Origin of name Group Period Block Standard atomic weight A r °(E) Density Melting point Boiling point Specific heat capacity Electronegativity Abundance in Earth's crust Origin Phase at r.t. Atomic number Z Symbol Name (g / cm 3) (K) (J / g · K) (mg / kg) 1 H Hydrogen: Greek elements hydro-and -gen, 'water-forming' 1 1 s-block: 1.0080