There are currently 118 known
chemical elements
A chemical element is a species of atoms that have a given number of protons in their nuclei, including the pure substance consisting only of that species. Unlike chemical compounds, chemical elements cannot be broken down into simpler sub ...
exhibiting many different physical and chemical properties. Amongst this diversity, scientists have found it useful to use names for various sets of elements, that illustrate similar properties, or their trends of properties. Many of these sets are formally recognized by the standards body
IUPAC
The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering Organizations working for the advancement of the chemical sciences, especially by developing nomenclature and terminology. It is ...
.
[ Retrieved 10 June 2012.]
The following collective names are recommended by IUPAC:
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Alkali metals
The alkali metals consist of the chemical elements lithium (Li), sodium (Na), potassium (K),The symbols Na and K for sodium and potassium are derived from their Latin names, ''natrium'' and ''kalium''; these are still the origins of the names ...
– The metals of group 1: Li, Na, K, Rb, Cs, Fr.
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Alkaline earth metals
The alkaline earth metals are six chemical elements in group 2 of the periodic table. They are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).. The elements have very similar properties: they are all ...
– The metals of group 2: Be, Mg, Ca, Sr, Ba, Ra.
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Transition elements
In chemistry, a transition metal (or transition element) is a chemical element in the d-block of the periodic table (groups 3 to 12), though the elements of group 12 (and less often group 3) are sometimes excluded. They are the elements that ca ...
– Elements in groups 3 to 11 or 3 to 12 (the latter equalling the d-block).
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Pnictogens
A pnictogen ( or ; from grc, wikt:πνίγω, πνῑ́γω "to choke" and wikt:-gen#English, -gen, "generator") is any of the chemical elements in group (periodic table), group 15 of the periodic table. Group 15 is also known as the nitro ...
– The elements of group 15: N, P, As, Sb, Bi. (Mc had not yet been named when the 2005 IUPAC Red Book was published, and its chemical properties are not yet experimentally known.)
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Chalcogens
The chalcogens (ore forming) ( ) are the chemical elements in group 16 of the periodic table. This group is also known as the oxygen family. Group 16 consists of the elements oxygen (O), sulfur (S), selenium (Se), tellurium (Te), and the radioa ...
– The elements of group 16: O, S, Se, Te, Po. (Lv had not yet been named when the 2005 IUPAC Red Book was published, and its chemical properties are not yet experimentally known.)
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Halogens
The halogens () are a group in the periodic table consisting of five or six chemically related elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At), and tennessine (Ts). In the modern IUPAC nomenclature, this group is ...
– The elements of group 17: F, Cl, Br, I, At. (Ts had not yet been named when the 2005 IUPAC Red Book was published, and its chemical properties are not yet experimentally known.)
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Noble gases
The noble gases (historically also the inert gases; sometimes referred to as aerogens) make up a class of chemical elements with similar properties; under standard conditions, they are all odorless, colorless, monatomic gases with very low chemi ...
– The elements of group 18: He, Ne, Ar, Kr, Xe, Rn. (Og had not yet been named when the 2005 IUPAC Red Book was published, and its chemical properties are not yet experimentally known.)
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Lanthanides
The lanthanide () or lanthanoid () series of chemical elements comprises the 15 metallic chemical elements with atomic numbers 57–71, from lanthanum through lutetium. These elements, along with the chemically similar elements scandium and ytt ...
– Elements 57–71: La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu.
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Actinides
The actinide () or actinoid () series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium. The actinide series derives its name from the first element in the series, actinium. The inform ...
– Elements 89–103: Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, Lr.
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Rare-earth metals
The rare-earth elements (REE), also called the rare-earth metals or (in context) rare-earth oxides or sometimes the lanthanides (yttrium and scandium are usually included as rare earths), are a set of 17 nearly-indistinguishable lustrous silve ...
– Sc, Y, plus the lanthanides.
*Inner transition elements – f-block elements.
*Main group elements – Elements in groups 1–2 or 13–18, except hydrogen.
Another common classification is by degree of metallic – metalloidal – nonmetallic behaviour and characteristics. There is no general agreement on the name to use for these sets. Very often these categories are marked by a background color in the periodic table.
* Transition elements are sometimes referred to as transition metals.
* Lanthanoids and actinoids are sometimes referred to as lanthanides and actinides respectively.
Many other names for sets of elements are in common use, and yet others have been used throughout history. These sets usually do not aim to cover the whole periodic table (as for example ''period'' does), and often overlap or have boundaries that differ between authors. Some examples:
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Metal
A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typicall ...
s and
nonmetal
In chemistry, a nonmetal is a chemical element that generally lacks a predominance of metallic properties; they range from colorless gases (like hydrogen) to shiny solids (like carbon, as graphite). The electrons in nonmetals behave differentl ...
s
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Metalloids
A metalloid is a type of chemical element which has a preponderance of properties in between, or that are a mixture of, those of metals and nonmetals. There is no standard definition of a metalloid and no complete agreement on which elements are ...
– Variously-defined group of elements with properties intermediate between metals and nonmetals.
In alphabetic order:
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Coinage metals
The coinage metals comprise, at a minimum, those metallic chemical elements which have historically been used as components in alloys used to mint coins. The term is not perfectly defined, however, since a number of metals have been used to mak ...
– Various metals used to mint coins, primarily the group 11 elements Cu, Ag, and Au.
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Earth metal – Old historic term, usually referred to the metals of groups 3 and 13, although sometimes others such as beryllium and chromium are included as well.
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Heavy metals
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Heavy metals are generally defined as ...
– Variously-defined group of metals, on the base of their density, atomic number, or toxicity.
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Heavy atom – term used in
computational chemistry
Computational chemistry is a branch of chemistry that uses computer simulation to assist in solving chemical problems. It uses methods of theoretical chemistry, incorporated into computer programs, to calculate the structures and properties of m ...
to refer to any element other than hydrogen and helium.
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Minor actinides
The minor actinides are the actinide elements in used nuclear fuel other than uranium and plutonium, which are termed the major actinides. The minor actinides include neptunium (element 93), americium (element 95), curium (element 96), berkeli ...
– Actinides found in significant quantities in nuclear fuel, other than U and Pu: Np, Am, Cm.
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Native metals
A native metal is any metal that is found pure in its metallic form in nature. Metals that can be found as native deposits singly or in alloys include aluminium, antimony, arsenic, bismuth, cadmium, chromium, cobalt, indium, iron, manganese, m ...
– Metals that occur pure in nature, including the noble metals and others such as Sn and Pb.
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Noble metals – Variously-defined group of metals that are generally resistant to corrosion. Usually includes Ag, Au, and the platinum-group metals.
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Non-ferrous metals
In metallurgy, non-ferrous metals are metals or alloys that do not contain iron (allotropes of iron, ferrite, and so on) in appreciable amounts.
Generally more costly than ferrous metals, non-ferrous metals are used because of desirable proper ...
- Metals or alloys that do not contain iron in appreciable amounts.
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Platinum group
The platinum-group metals (abbreviated as the PGMs; alternatively, the platinoids, platinides, platidises, platinum group, platinum metals, platinum family or platinum-group elements (PGEs)) are six noble, precious metallic elements clustered to ...
– Ru, Rh, Pd, Os, Ir, Pt.
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Post-transition metals
The metallic elements in the periodic table located between the transition metals and the chemically weak nonmetallic metalloids have received many names in the literature, such as ''post-transition metals'', ''poor metals'', ''other metals'', ...
– The metals coming after the transition metals. Many other names have been used for this set, and its borders are not agreed on.
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Precious metals
Precious metals are rare, naturally occurring metallic chemical elements of high economic value.
Chemically, the precious metals tend to be less reactive than most elements (see noble metal). They are usually ductile and have a high lustre. ...
– Variously-defined group of non-radioactive metals of high economical value.
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Superactinides
An extended periodic table theorises about chemical elements beyond those currently known in the periodic table and proven. , the element with the highest atomic number known is oganesson (''Z'' = 118), which completes the seventh period (row) ...
– Hypothetical series of elements 121 to 157, which includes a predicted "g-block" of the periodic table.
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Transactinide elements
Superheavy elements, also known as transactinide elements, transactinides, or super-heavy elements, are the chemical elements with atomic number greater than 103. The superheavy elements are those beyond the actinides in the periodic table; the ...
– Elements after the actinides (atomic number greater than 103).
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Transplutonium elements
The transuranium elements (also known as transuranic elements) are the chemical elements with atomic numbers greater than 92, which is the atomic number of uranium. All of these elements are unstable and decay radioactively into other elements ...
– Elements with atomic number greater than 94.
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Transuranium elements
The transuranium elements (also known as transuranic elements) are the chemical elements with atomic numbers greater than 92, which is the atomic number of uranium. All of these elements are unstable and decay radioactively into other elements. ...
– Elements with atomic number greater than 92.
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Valve metal - a metal which, in an electrolytic cell, passes current in only one direction.
References
External links
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{{Navbox periodic table
Chemical nomenclature