Chemistry

What is a chemical element? Properties and definition

What is a chemical element? Properties and definition

A chemical element is a pure substance with certain physical and chemical properties. The atomic nucleus of each element consists of protons and neutrons. The number of protons in the nucleus of an atom - atomic number - is unique for each chemical element.

Sometimes, some authors refer to a chemical species to refer to a certain atom. However, this term is also used to refer to other substances such as molecules, ions, etc.

Each chemical element has its Latin name and the chemical symbol consisting of one or two letters. The names and symbols of the elements are regulated by the IUPAC and are reflected in Mendeleev's periodic table of elements.

The form of existence of chemical elements in free form are simple substances. It is necessary to distinguish between chemical elements (abstract objects described through their characteristics) and the corresponding material objects: simple chemical compounds (with certain physical and chemical properties).

A particular group of elements are the noble gases. Noble gases are a group of chemical elements with very similar properties: they are odorless, colorless monatomic gases and have very low chemical reactivity.

Chemical elements can combine with each other to form another defined chemical composition through chemical reactions. For example, the element oxygen and hydrogen can combine to form water.

How many are the chemical elements?

118 chemical elements are known, of which 94 are found in nature (some are only found in small quantities). The remaining 24 are obtained artificially as a result of nuclear reactions.

Man-made chemical elements have a higher atomic number than uranium. Its synthesis was initially carried out by the repeated capture of neutrons by uranium nuclei under conditions of intense neutron flux in nuclear reactors.

Uranium isotopes are used to make nuclear fuel. They have a very unstable nature that makes them suitable for the nuclear energy industry.

What does the name of the elements depend on?

The right to propose a name for a new chemical element is granted to the discoverers. However, this name must adhere to certain rules. Publishing a new discovery is verified within a few years by independent laboratories. If the existence of the element is confirmed, the International Union of Pure and Applied Chemistry officially approves the name of the new element.

The 118 elements known as of December 2016 have permanent names approved by IUPAC. From the time of the opening request to the approval of the IUPAC name, the item appears under a temporary systematic name.

Unopened or unapproved elements are often named using the system used by Mendeleev, that is, by the name of the higher homolog in the periodic table. In this case, the prefixes "ek-" or (rarely) "dvi-" are added, which means Sanskrit numbers "one" and "two" depending on whether the homolog is 1 or 2 periods higher.

What are the chemical elements?

Chemical elements are classified on the periodic table of elements.

What are the chemical elements?  periodic table of elements

Known chemical elements are as follows:

Chemical element Symbol Atomic number (Z) Atomic weight (u)
Hydrogen H 1 1.0079
Helio He 2 4.0026
Lithium Li 3 6941
Beryllium Be 4 9.0122
Boro B 5 10811
Carbon C 6 12.0107
Nitrogen N 7 14.0067
Oxygen O 8 15.9994
Fluorine F 9 18.9984
Neon Ne 10 20.1797
Sodium Na 11 22.9897
Magnesium Mg 12 24305
Aluminum Al 13 26.9815
Silicon Si 14 28.0855
Match P 15 30.9738
Sulfur S 16 32065
Chlorine Cl 17 35453
Argon Ar 18 39948
Potassium K 19 39.0983
Football Ca 20 40078
Scandium Sc 21 44,9559
Titanium Ti 22 47867
Vanadium V 23 50.9415
Chrome Cr 24 51,9961
Manganese Mn 25 54938
Iron Fe 26 55845
Cobalt Co 27 58,9332
Nickel Ni 28 58.6934
Copper Cu 29 63546
Zinc Zn 30 65.39
Gallium Ga 31 69723
Germany Ge 32 72.64
Arsenic As 33 74.9216
Selenium Se 34 78.96
Bromo Br 35 79904
Krypton Kr 36 83.8
Rubidio Rb 37 85.4678
Strontium Sr 38 87.62
Yttrium Y 39 88,9059
Zirconium Zr 40 91224
Niobium Nb 41 92,9064
Molybdenum Mo 42 95.94
Technetium Tc 43 98
Rutenio Ru 44 101.07
Rodio Rh 45 102,9055
Palladium Pd 46 106.42
The payment Ag 47 107,8682
Cadmium Cd 48 112411
Indian In 49 114818
Tin Sn 50 118.71
Antimony Sb 51 121.76
Teluro Te 52 127.6
Iodine I 53 126.9045
Xenon Xe 54 131293
Cesium Cs 55 132.9055
Barium Ba 56 137327
Lantano La 57 138.9055
Cerium Ce 58 140116
Praseodimio Pr 59 140.9077
Neodymium Nd 60 144.24
Prometheus Pm 61 145
Samaria Sm 62 150.36
Europe Eu 63 151964
Gadolinium Gd 64 157.25
Terbio Tb 65 158,9253
Disprosio Dy 66 162.5
Holmio Ho 67 164,9303
Erbio Er 68 167259
Thulium Tm 69 168.9342
Iterbio Yb 70 173.04
Lutecio Lu 71 174967
Shaping Hf 72 178.49
Tantalum Ta 73 180,9479
Tungsten W 74 183.84
Renio Re 75 186207
Osmio Os 76 190.23
Iridium Ir 77 192217
Platinum Pt 78 195078
Oro Au 79 196.9665
Mercury Hg 80 200.59
Thallium Tl 81 204.3833
Lead Pb 82 207.2
Bismuth Bi 83 208,9804
Polonium Po 84 209
Astato At 85 210
Radon Rn 86 222
France Fr 87 223
Radio Ra 88 226
Actinio Ac 89 227
Thorium Th 90 232.0381
Protactinio Pa 91 231.0359
Uranium U 92 238.0289
Neptune Np 93 237
Plutonium Pu 94 244
Americio Am 95 243
Curio Cm 96 247
Berkelio Bk 97 247
Californio Cf 98 251
Einstenio Es 99 252
Fermio Fm 100 257
Mendelevio Md 101 258
Nobel No 102 259
Laurencio Lr 103 262
Rutherfordio Rf 104 261
Dubnio Db 105 262
Seaborgio Sg 106 266
Bohrio Bh 107 264
Hassio Hs 108 277
Meitnerio Mt 109 268
Darmstadtio Ds 110 281
Roentgenio Rg 111 272
Copernicus Cn 112 285
Nihonio Nh 113 286
Flerovio Fl 114 289
Moscow Mc 115 288
Livermorio Lv 116 292
Teneso Ts 117 294
Oganesón Og 118 294

 

How is a chemical element presented?

Chemical element symbols are used as abbreviations for the name of the elements. As a symbol, they usually take the initial letter of the item's name and, if necessary, add the next or one of the following. These are usually the initial letters of the Latin names of the elements.

representation of a chemical element uraniumSuch a system of chemical symbols was proposed in 1814 by the Swedish chemist J. Berzelius. The elements used before the official approval of their names and permanent symbols consist of three letters, which means that the Latin names of the three digits in the decimal notation of their atomic number. The notation system for higher homologues described above (Eka-Rn, Eka-Pb, etc.) is also used.

The smaller numbers next to the element symbol indicate:

  • The atomic mass in the upper left.

  • Atomic number in the lower left.

Author:
Publication Date: February 12, 2020
Last Revision: August 29, 2021