What are the two lightest chemical elements? From the Guinness Book of Records: elements. How did the periodic table of chemical elements appear?

We present a selection of chemical records from the Guinness Book of Records.
Due to the fact that new substances are constantly being discovered, this selection is not permanent.

Chemical records for inorganic substances

• The most common element in earth's crust— oxygen O. Its weight content is 49% of the mass of the earth’s crust.
• The rarest element in the earth's crust is astatine At. Its content in the entire earth's crust is only 0.16 g. The second place in rarity is occupied by the French Fr.
• The most common element in the universe is hydrogen H. Approximately 90% of all atoms in the universe are hydrogen. The second most abundant element in the universe is helium He.
• The strongest stable oxidizing agent is a complex of krypton difluoride and antimony pentafluoride. Due to its strong oxidizing effect (oxidizes almost all elements in higher degrees oxidation, including oxidizes air oxygen) it is very difficult for it to measure the electrode potential. The only solvent that reacts with it slowly enough is anhydrous hydrogen fluoride.
• The most dense substance on planet Earth - osmium. The density of osmium is 22.587 g/cm3.
• The lightest metal is lithium Li. The density of lithium is 0.543 g/cm 3 .
• The densest compound is ditungsten carbide W 2 C. The density of ditungsten carbide is 17.3 g/cm 3 .
• Currently, the lowest density solids are graphene aerogels. They are a system of graphene and nanotubes filled with air layers. The lightest of these aerogels has a density of 0.00016 g/cm 3 . The previous solid with the lowest density is silicon airgel (0.005 g/cm3). Silicon airgel is used in the collection of micrometeorites present in the tails of comets.
• The lightest gas and, at the same time, the lightest non-metal is hydrogen. The mass of 1 liter of hydrogen is only 0.08988 g. In addition, hydrogen is also the most fusible non-metal at normal pressure (melting point is -259.19 0 C).
• The lightest liquid is liquid hydrogen. The mass of 1 liter of liquid hydrogen is only 70 grams.
• The heaviest inorganic gas at room temperature is tungsten hexafluoride WF 6 (boiling point +17 0 C). The density of tungsten hexafluoride in gas form is 12.9 g/l. Among gases with a boiling point below 0 °C, the record belongs to tellurium hexafluoride TeF 6 with a gas density at 25 0 C of 9.9 g/l.
• The most expensive metal in the world is Californian Cf. The price of 1 gram of the 252 Cf isotope reaches 500 thousand US dollars.
• Helium He is the substance with the lowest boiling point. Its boiling point is -269 0 C. Helium is the only substance that does not have a melting point at normal pressure. Even at absolute zero it remains liquid and can only be obtained in solid form under pressure (3 MPa).
• The most refractory metal and the substance with the highest boiling point is tungsten W. The melting point of tungsten is +3420 0 C, and the boiling point is +5680 0 C.
• The most refractory material is an alloy of hafnium and tantalum carbides (1:1) (melting point +4215 0 C)
• The most fusible metal is mercury. The melting point of mercury is -38.87 0 C. Mercury is also the heaviest liquid, its density at 25°C is 13.536 g/cm 3 .
• The most acid-resistant metal is iridium. Until now, not a single acid or mixture thereof is known in which iridium would dissolve. However, it can be dissolved in alkalis with oxidizing agents.
• The strongest stable acid is a solution of antimony pentafluoride in hydrogen fluoride.
• The hardest metal is chromium Cr.
• The softest metal at 25 0 C is cesium.
• The hardest material is still diamond, although there are already about a dozen substances approaching it in hardness (boron carbide and nitride, titanium nitride, etc.).
• The most electrically conductive metal at room temperature is silver Ag.
• The lowest speed of sound in liquid helium is at a temperature of 2.18 K, it is only 3.4 m/s.
• The highest speed of sound in diamond is 18600 m/s.
• The isotope with the shortest half-life is Li-5, which decays in 4.4·10-22 seconds (proton ejection). Due to such a short lifetime, not all scientists recognize the fact of its existence.
• The isotope with the longest measured half-life is Te-128, with a half-life of 2.2 1024 years (double β decay).
• Most number stable isotopes have xenon and cesium (36 each).
• The most short names chemical elements possess boron and iodine (3 letters each).
• The longest chemical element names (eleven letters each) are protactinium Pa, rutherfordium Rf, darmstadtium Ds.

Chemical records for organic substances

• The heaviest organic gas at room temperature and the heaviest gas among all at room temperature is N-(octafluorobut-1-ylidene)-O-trifluoromethylhydroxylamine (bp +16 C). Its density as a gas is 12.9 g/l. Among gases with a boiling point below 0°C, the record belongs to perfluorobutane with a gas density at 0°C of 10.6 g/l.
• The most bitter substance is denatonium saccharinate. Combination of denatonium benzoate with sodium salt saccharin produced a substance 5 times more bitter than the previous record holder (denatonium benzoate).
• The most non-toxic organic substance is methane. When its concentration increases, intoxication occurs due to a lack of oxygen, and not as a result of poisoning.
• The strongest adsorbent for water was obtained in 1974 from a starch derivative, acrylamide and acrylic acid. This substance is capable of holding water, the mass of which is 1300 times greater than its own.
• The strongest adsorbent for petroleum products is carbon airgel. 3.5 kg of this substance can absorb 1 ton of oil.
• The most smelly compounds are ethyl selenol and butyl mercaptan - their smell resembles a combination of the smells of rotting cabbage, garlic, onions and sewage at the same time.
• The sweetest substance is N-((2,3-methylenedioxyphenylmethylamino)-(4-cyanophenylimino)methyl)aminoacetic acid (lugduname). This substance is 205,000 times sweeter than a 2% sucrose solution. There are several analogues with similar sweetness. Of the industrial substances, the sweetest is talin (a complex of thaumatin and aluminum salts), which is 3,500 - 6,000 times sweeter than sucrose. IN lately V food industry neotame appeared with a sweetness 7000 times higher than sucrose.
• The slowest enzyme is nitrogenase, which catalyzes the absorption of atmospheric nitrogen by nodule bacteria. The complete cycle of converting one nitrogen molecule into 2 ammonium ions takes one and a half seconds.
• The organic substance with the highest nitrogen content is either bis(diazotetrazolyl)hydrazine C2H2N12, containing 86.6% nitrogen, or tetraazidomethane C(N3)4, containing 93.3% nitrogen (depending on whether the latter is considered organic or not) . These are explosives that are extremely sensitive to shock, friction and heat. From inorganic substances The record, of course, belongs to gaseous nitrogen, and among compounds - hydronitric acid HN 3.
• The longest chemical name has 1578 characters in English spelling and is a modified nucleotide sequence. This substance is called: Adenosene. N--2′-O-(tetrahydromethoxypyranyl)adenylyl-(3'→5′)-4-deamino-4-(2,4-dimethylphenoxy)-2′-O-(tetrahydromethoxypyranyl)cytidylyl-(3'→5 ′)-4-deamino-4-(2,4-dimethylphenoxy)-2′-O-(tetrahydromethoxypyranyl)cytidylyl-(3'→5′)-N--2′-O-(tetrahydromethoxypyranyl)cytidylyl-(3 '→5′)-N--2′-O-(tetrahydromethoxypyranyl)cytidylyl-(3'→5′)-N--2′-O-(tetrahydromethoxypyranyl)guanylyl-(3'→5′)-N- -2′-O-(tetrahydromethoxypyranyl)guanylyl-(3'→5′)-N--2′-O-(tetrahydromethoxypyranyl)adenylyl-(3'→5′)-N--2′-O-(tetrahydromethoxypyranyl )cytidylyl-(3'→5′)-4-deamino-4-(2,4-dimethylphenoxy)-2′-O-(tetrahydromethoxypyranyl)cytidylyl-(3'→5′)-4-deamino-4-( 2,4-dimethylphenoxy)-2′-O-(tetrahydromethoxypyranyl)cytidylyl-(3'→5′)-N--2′-O-(tetrahydromethoxypyranyl)guanylyl-(3'→5′)-4-deamino- 4-(2,4-dimethylphenoxy)-2′-O-(tetrahydromethoxypyranyl)cytidylyl-(3'→5′)-N--2′-O-(tetrahydromethoxypyranyl)cytidylyl-(3'→5′)-N --2′-O-(tetrahydromethoxypyranyl)cytidylyl-(3'→5′)-N--2′-O-(tetrahydromethoxypyranyl)adenylyl-(3'→5′)-N--2′-O-( tetrahydromethoxypyranyl)cytidylyl-(3'→5′)-N--2′-O-(tetrahydromethoxypyranyl)cytidylyl-(3'→5′)-N--2′,3′-O-(methoxymethylene)-octadecakis( 2-chlorophenyl)ester. 5′-.
• The longest chemical name has DNA isolated from human mitochondria and consisting of 16569 nucleotide pairs. The full name of this compound contains about 207,000 characters.
• System from the largest number immiscible liquids, which again separates into components after mixing, contains 5 liquids: mineral oil, silicone oil, water, benzyl alcohol and N-perfluoroethylperfluoropyridine.
• The densest organic liquid at room temperature is diiodomethane. Its density is 3.3 g/cm3.
• The most refractory individual organic substances are some aromatic compounds. Of the condensed ones, this is tetrabenzheptacene (melting point +570 C), of the non-condensed ones - p-septiphenyl (melting point +545 C). There are organic compounds for which the melting point has not been accurately measured, for example, for hexabenzocoronene it is indicated that its melting point is above 700 C. The thermal crosslinking product of polyacrylonitrile decomposes at a temperature of about 1000 C.
• The organic substance with the highest boiling point is hexatriaconylcyclohexane. It boils at +551°C.
• The longest alkane is nonacontatrictan C390H782. It was specially synthesized to study the crystallization of polyethylene.
• The longest protein is the muscle protein titin. Its length depends on the type of living organism and location. Mouse titin, for example, has 35,213 amino acid residues (mol. weight 3,906,488 Da), human titin has a length of up to 33,423 amino acid residues (mol. weight 3,713,712 Da).
• The longest genome is that of the plant Paris japonica. It contains 150,000,000,000 nucleotide pairs - 50 times more than in humans (3,200,000,000 nucleotide pairs).
• The largest molecule is the DNA of the first human chromosome. It contains about 10,000,000,000 atoms.
• The individual explosive with the highest detonation speed is 4,4′-dinitroazofuroxan. Its measured detonation speed was 9700 m/s. According to unverified data, ethyl perchlorate has an even higher detonation rate.
• The individual explosive with the highest heat of explosion is ethylene glycol dinitrate. Its heat of explosion is 6606 kJ/kg.
• The strongest organic acid is pentacyanocyclopentadiene.
• The most strong foundation possibly 2-methylcyclopropenyllithium. The strongest nonionic base is phosphazene, which has a rather complex structure.

Categories

The universe hides many secrets in its depths. For a long time, people have sought to unravel as many of them as possible, and, despite the fact that this does not always work out, science is moving forward by leaps and bounds, allowing us to learn more and more about our origins. So, for example, many will be interested in what is the most common one in the Universe. Most people will immediately think of water, and they will be partly right, because the most common element is hydrogen.

The most abundant element in the Universe

It is extremely rare for people to encounter hydrogen in its pure form. However, in nature it is very often found in association with other elements. For example, when it reacts with oxygen, hydrogen turns into water. And this is far from the only compound that includes this element; it is found everywhere not only on our planet, but also in space.

How did the Earth appear?

Many millions of years ago, hydrogen, without exaggeration, became building material for the entire Universe. After all, after the big bang, which became the first stage of the creation of the world, nothing existed except this element. elementary because it consists of only one atom. Over time, the most abundant element in the universe began to form clouds, which later became stars. And already inside them reactions took place, as a result of which new, more complex elements appeared, giving rise to planets.

Hydrogen

This element accounts for about 92% of the atoms in the Universe. But it is found not only in stars and interstellar gas, but also in common elements on our planet. Most often it exists in a bound form, and the most common compound is, of course, water.

In addition, hydrogen is part of a number of carbon compounds that form oil and natural gas.

Conclusion

Despite the fact that it is the most common element throughout the world, surprisingly, it can be dangerous for humans because it sometimes catches fire when it reacts with air. To understand how important a role hydrogen played in the creation of the Universe, it is enough to realize that without it nothing living would have appeared on Earth.

A chemical element is a collective term that describes a collection of atoms simple substance, i.e. one that cannot be divided into any simpler (according to the structure of their molecules) components. Imagine being given a piece of pure iron and being asked to separate it into its hypothetical constituents using any device or method ever invented by chemists. However, you can't do anything; the iron will never be divided into something simpler. A simple substance - iron - corresponds to the chemical element Fe.

Theoretical definition

The experimental fact noted above can be explained using the following definition: a chemical element is an abstract collection of atoms (not molecules!) of the corresponding simple substance, i.e. atoms of the same type. If there was a way to look at each of the individual atoms in the piece of pure iron mentioned above, then they would all be iron atoms. In contrast to this, chemical compound, for example, iron oxide, always contains at least two various types atoms: iron atoms and oxygen atoms.

Terms you should know

Atomic mass: The mass of protons, neutrons, and electrons that make up an atom of a chemical element.

Atomic number: The number of protons in the nucleus of an element's atom.

Chemical symbol: letter or pair Latin letters, representing the designation of this element.

Chemical compound: a substance that is made up of two or more chemical elements, connected to each other in a certain proportion.

Metal: An element that loses electrons in chemical reactions with other elements.

Metalloid: An element that reacts sometimes as a metal and sometimes as a non-metal.

Non-metal: an element that seeks to gain electrons in chemical reactions with other elements.

Periodic Table of Chemical Elements: A system of classifying chemical elements according to their atomic numbers.

Synthetic element: One that is produced artificially in a laboratory and is generally not found in nature.

Natural and synthetic elements

Ninety-two chemical elements occur naturally on Earth. The rest were obtained artificially in laboratories. A synthetic chemical element is usually a product nuclear reactions in particle accelerators (devices used to increase the speed of subatomic particles such as electrons and protons) or nuclear reactors(devices used to control the energy released during nuclear reactions). The first synthetic element with atomic number 43 was technetium, discovered in 1937 by Italian physicists C. Perrier and E. Segre. Apart from technetium and promethium, all synthetic elements have nuclei larger than uranium. The last synthetic chemical element to receive its name is livermorium (116), and before it was flerovium (114).

Two dozen common and important elements

Name	Symbol	Percentage of all atoms *				Properties of chemical elements (under normal room conditions)
		In the universe	In the earth's crust	In sea water	In the human body
Aluminum	Al	-	6,3	-	-	Lightweight, silver metal
Calcium	Ca	-	2,1	-	0,02	Found in natural minerals, shells, bones
Carbon	WITH	-	-	-	10,7	The basis of all living organisms
Chlorine	Cl	-	-	0,3	-	Poisonous gas
Copper	Cu	-	-	-	-	Red metal only
Gold	Au	-	-	-	-	Yellow metal only
Helium	He	7,1	-	-	-	Very light gas
Hydrogen	N	92,8	2,9	66,2	60,6	The lightest of all elements; gas
Iodine	I	-	-	-	-	Non-metal; used as an antiseptic
Iron	Fe	-	2,1	-	-	Magnetic metal; used to produce iron and steel
Lead	Pb	-	-	-	-	Soft, heavy metal
Magnesium	Mg	-	2,0	-	-	Very light metal
Mercury	Hg	-	-	-	-	Liquid metal; one of two liquid elements
Nickel	Ni	-	-	-	-	Corrosion-resistant metal; used in coins
Nitrogen	N	-	-	-	2,4	Gas, the main component of air
Oxygen	ABOUT	-	60,1	33,1	25,7	Gas, the second important one air component
Phosphorus	R	-	-	-	0,1	Non-metal; important for plants
Potassium	TO	-	1.1	-	-	Metal; important for plants; usually called "potash"

* If the value is not specified, then the element is less than 0.1 percent.

The Big Bang as the root cause of matter formation

What chemical element was the very first in the Universe? Scientists believe the answer to this question lies in stars and the processes by which stars are formed. The universe is believed to have come into being at some point in time between 12 and 15 billion years ago. Until this moment, nothing existing except energy is thought of. But something happened that turned this energy into a huge explosion (the so-called Big Bang). In the next seconds after big bang matter began to form.

The first simplest forms of matter to appear were protons and electrons. Some of them combine to form hydrogen atoms. The latter consists of one proton and one electron; it is the simplest atom that can exist.

Slowly, over long periods of time, hydrogen atoms began to cluster together in certain areas of space, forming dense clouds. The hydrogen in these clouds was pulled into compact formations by gravitational forces. Eventually these clouds of hydrogen became dense enough to form stars.

Stars as chemical reactors of new elements

A star is simply a mass of matter that generates energy from nuclear reactions. The most common of these reactions involves the combination of four hydrogen atoms forming one helium atom. Once stars began to form, helium became the second element to appear in the Universe.

As stars get older, they switch from hydrogen-helium nuclear reactions to other types. In them, helium atoms form carbon atoms. Later, carbon atoms form oxygen, neon, sodium and magnesium. Later still, neon and oxygen combine with each other to form magnesium. As these reactions continue, more and more chemical elements are formed.

The first systems of chemical elements

More than 200 years ago, chemists began to look for ways to classify them. In the mid-nineteenth century, about 50 chemical elements were known. One of the questions that chemists sought to resolve. boiled down to the following: is a chemical element a substance completely different from any other element? Or some elements related to others in some way? Is there a general law that unites them?

Chemists suggested various systems chemical elements. For example, the English chemist William Prout in 1815 suggested that the atomic masses of all elements are multiples of the mass of the hydrogen atom, if we take it equal to one, i.e. they must be integers. At that time, the atomic masses of many elements had already been calculated by J. Dalton in relation to the mass of hydrogen. However, if this is approximately the case for carbon, nitrogen, and oxygen, then chlorine with a mass of 35.5 did not fit into this scheme.

The German chemist Johann Wolfgang Dobereiner (1780 – 1849) showed in 1829 that three elements of the so-called halogen group (chlorine, bromine and iodine) could be classified by their relative atomic masses. The atomic weight of bromine (79.9) turned out to be almost exactly the average of the atomic weights of chlorine (35.5) and iodine (127), namely 35.5 + 127 ÷ 2 = 81.25 (close to 79.9). This was the first approach to constructing one of the groups of chemical elements. Dobereiner discovered two more such triads of elements, but he was unable to formulate a general periodic law.

How did the periodic table of chemical elements appear?

Most of the early classification schemes were not very successful. Then, around 1869, almost the same discovery was made by two chemists at almost the same time. Russian chemist Dmitri Mendeleev (1834-1907) and German chemist Julius Lothar Meyer (1830-1895) proposed organizing elements that have similar physical and chemical properties, into an ordered system of groups, series and periods. At the same time, Mendeleev and Meyer pointed out that the properties of chemical elements periodically repeat depending on their atomic weights.

Today Mendeleev is generally considered the discoverer periodic law, because he took one step that Meyer didn't take. When all the elements were arranged in the periodic table, some gaps appeared. Mendeleev predicted that these were places for elements that had not yet been discovered.

However, he went even further. Mendeleev predicted the properties of these not yet discovered elements. He knew where they were located on the periodic table, so he could predict their properties. Remarkably, every chemical element Mendeleev predicted, gallium, scandium, and germanium, was discovered less than ten years after he published his periodic law.

Short form of the periodic table

There have been attempts to calculate how many options graphic image The periodic table has been proposed by various scientists. It turned out that there were more than 500. Moreover, 80% total number options are tables, and the rest is geometric shapes, mathematical curves, etc. As a result practical application found four types of tables: short, half-long, long and ladder (pyramidal). The latter was proposed by the great physicist N. Bohr.

The picture below shows the short form.

In it, chemical elements are arranged in ascending order of their atomic numbers from left to right and from top to bottom. Thus, the first chemical element of the periodic table, hydrogen, has atomic number 1 because the nuclei of hydrogen atoms contain one and only one proton. Likewise, oxygen has atomic number 8 since the nuclei of all oxygen atoms contain 8 protons (see figure below).

The main structural fragments of the periodic system are periods and groups of elements. In six periods, all cells are filled, the seventh is not yet completed (elements 113, 115, 117 and 118, although synthesized in laboratories, have not yet been officially registered and do not have names).

Groups are divided into main (A) and secondary (B) subgroups. Elements of the first three periods, each containing one row, are included exclusively in the A-subgroups. The remaining four periods include two rows.

Chemical elements in the same group tend to have similar chemical properties. Thus, the first group consists of alkali metals, the second - alkaline earth metals. Elements located in the same period have properties that slowly change from alkali metal to a noble gas. The figure below shows how one of the properties - atomic radius - changes for individual elements in the table.

Long period form of the periodic table

It is shown in the figure below and is divided in two directions, by rows and by columns. There are seven period rows, as in the short form, and 18 columns, called groups or families. In fact, the increase in the number of groups from 8 in the short form to 18 in the long form is obtained by placing all the elements in periods, starting from the 4th, not in two, but in one line.

Two different systems numbering is used for groups, as shown at the top of the table. The Roman numeral system (IA, IIA, IIB, IVB, etc.) has traditionally been popular in the United States. Another system (1, 2, 3, 4, etc.) is traditionally used in Europe and was recommended for use in the USA several years ago.

The appearance of the periodic tables in the figures above is a little misleading, as with any such published table. The reason for this is that the two groups of elements shown at the bottom of the tables should actually be located within them. The lanthanides, for example, belong to period 6 between barium (56) and hafnium (72). Additionally, actinides belong to period 7 between radium (88) and rutherfordium (104). If they were inserted into a table, it would become too wide to fit on a piece of paper or wall chart. Therefore, it is customary to place these elements at the bottom of the table.

Most common

Lithosphere. Oxygen (O), 46.60% by weight. Discovered in 1771 by Karl Scheele (Sweden).
Atmosphere. Nitrogen (N), 78.09% by volume, 75.52% by mass. Discovered in 1772 by Rutherford (Great Britain).
Universe. Hydrogen (H), 90% of the total substance. Discovered in 1776 by Henry Cavendish (Great Britain).

Rarest (out of 94)

Lithosphere.
Astatine (At): 0.16 g in the earth's crust. Opened in 1940 by Corson (USA) and employees. The naturally occurring isotope astatine 215 (215At) (discovered in 1943 by B. Karlik and T. Bernert, Austria) exists in quantities of only 4.5 nanograms.
Atmosphere.
Radon (Rn): only 2.4 kg (6·10–20 volume of one part per million). Opened in 1900 by Dorn (Germany). The concentration of this radioactive gas in areas of granite rock deposits is believed to have caused a number of cancers. Total weight radon, located in the earth's crust, from which atmospheric gas reserves are replenished, is 160 tons.

The lightest

Gas:
Hydrogen (H) has a density of 0.00008989 g/cm3 at a temperature of 0°C and a pressure of 1 atm. Discovered in 1776 by Cavendish (Great Britain).
Metal.
Lithium (Li), with a density of 0.5334 g/cm3, is the lightest of all solids. Discovered in 1817 by Arfvedson (Sweden).

Maximum Density

Osmium (Os), with a density of 22.59 g/cm3, is the heaviest of all solids. Discovered in 1804 by Tennant (Great Britain).

Heaviest gas

It is radon (Rn), the density of which is 0.01005 g/cm3 at 0°C. Opened in 1900 by Dorn (Germany).

Last received

Element 108, or unniloctium (Uno). This provisional name is given by the International Union of Pure and Applied Chemistry (IUPAC). Obtained in April 1984 by G. Münzenberg and co-workers (West Germany), who observed only 3 atoms of this element in the laboratory of the Society for Heavy Ion Research in Darmstadt. In June of the same year, a message appeared that this element had also been obtained by Yu.Ts. Oganesyan and collaborators at the Joint Institute for Nuclear Research, Dubna, USSR.

A single unnilenium atom (Une) was obtained by bombarding bismuth with iron ions in the laboratory of the Heavy Ion Research Society, Darmstadt, West Germany, on August 29, 1982. It has the highest atomic number (element 109) and the highest atomic mass (266). . According to the most preliminary data, Soviet scientists observed the formation of the isotope of element 110 c atomic mass 272 (preliminary name - ununnilium (Uun)).

The cleanest

Helium-4 (4He), obtained in April 1978 by P.V. McLintock of Lancaster University, USA, has less than 2 parts of impurities per 1015 parts of volume.

The hardest

Carbon (C). In its allotropic form, diamond has a Knoop hardness of 8400. Known since prehistoric times.

The most expensive

Californian (Cf) was sold in 1970 at a price of $10 per microgram. Opened in 1950 by Seaborg (USA) and employees.

The most flexible

Gold (Au). From 1 g you can draw a wire 2.4 km long. Known since 3000 BC.

Highest tensile strength

Boron (B) – 5.7 GPa. Discovered in 1808 by Gay-Lussac and Thénard (France) and H. Davy (Great Britain).

Melting/boiling point

Lowest.
Among non-metals, helium-4 (4He) has the lowest melting point -272.375°C at a pressure of 24.985 atm and the lowest boiling point -268.928°C. Helium was discovered in 1868 by Lockyer (Great Britain) and Jansen (France). Monatomic hydrogen (H) must be an incompressible superfluid gas. Among metals, the corresponding parameters for mercury (Hg) are –38.836°C (melting point) and 356.661°C (boiling point).
The highest.
Among non-metals, the most high point melting point and boiling point of carbon (C), known since prehistoric times: 530°C and 3870°C. However, it seems controversial that graphite is stable at high temperatures. Transitioning from a solid to a vapor state at 3720°C, graphite can be obtained as a liquid at a pressure of 100 atm and a temperature of 4730°C. Among metals, the corresponding parameters for tungsten (W) are 3420°C (melting point) and 5860°C (boiling point). Opened in 1783 by H.H. and F. d'Eluyarami (Spain).

Isotopes

Largest quantity isotopes(36 each) for xenon (Xe), discovered in 1898 by Ramsay and Travers (Great Britain), and for cesium (Cs), discovered in 1860 by Bunsen and Kirchhoff (Germany). Hydrogen (H) has the smallest amount (3: protium, deuterium and tritium), discovered in 1776 by Cavendish (Great Britain).

The most stable

Tellurium-128 (128Te), according to double beta decay, has a half-life of 1.5 1024 years. Tellurium (Te) was discovered in 1782 by Müller von Reichenstein (Austria). The 128Te isotope was first discovered in its natural state in 1924 by F. Aston (Great Britain). Data on its superstability were again confirmed in 1968 by studies by E. Alexander Jr., B. Srinivasan and O. Manuel (USA). The alpha decay record belongs to samarium-148 (148Sm) – 8·1015 years. The beta decay record belongs to the cadmium isotope 113 (113Cd) – 9·1015 years. Both isotopes were discovered in their natural state by F. Aston, respectively, in 1933 and 1924. The radioactivity of 148Sm was discovered by T. Wilkins and A. Dempster (USA) in 1938, and the radioactivity of 113Cd was discovered in 1961 by D. Watt and R. Glover (Great Britain).

The most unstable

The lifetime of lithium-5 (5Li) is limited to 4.4·10–22 s. The isotope was first discovered by E. Titterton (Australia) and T. Brinkley (Great Britain) in 1950.

The most poisonous

Among non-radioactive substances, the most stringent restrictions are set for beryllium (Be) - the maximum permissible concentration (MAC) of this element in the air is only 2 μg/m3. Among radioactive isotopes, existing in nature or produced by nuclear installations, the most stringent limits on the content in the air are set for thorium-228 (228Th), which was first discovered by Otto Hahn (Germany) in 1905 (2.4 10–16 g/m3) , and in terms of content in water - for radium-228 (228Ra), discovered by O. Gan in 1907 (1.1·10–13 g/l). From an environmental point of view, they have significant half-lives (i.e. over 6 months).