Periodic Table of the elements
Grupo101112131415161718 Grupo101112131415161718
I II III IV V VI VII VIII I II III IV V VI VII VIII
Period Period
1
2
He He
3
Li 4
Be 5
6
7
8
9
10
Ne Ne
11
Na 12
Mg 13
At 14
If 15
16
17
CL 18
Ar Ar
19
20
CA 21
SC 22
Ti 23
24
Cr 25
Mn 26
Fe 27
Co 28
Ni 29
Cu 30
Zn 31
Ga 32
Ge 33
As 34
SE 35
BR 36
Kr Kr
37
Rb 38
SR 39
40
Zr 41
Nb 42
Mo 43
TC 44
Ru 45
Rh 46
Pd 47
Ag 48
CD 49
In 50
Sn 51
SB 52
TE 53
54
Xe Xe
55
56 Cs
Ba * 72
73 Hf
Ta 74
75
Re 76
Os 77
Go 78
Pt 79
Au 80
Hg 81
Tl 82
Pb 83
Bi 84
Po 85
At 86
Rn Rn
87
FR 88
Ra ** 104
Rf 105
106 Db
Sg 107
Bh 108
Hs 109
MT 110
111 Ds
112 Rg
113 Uub
114 Uut
Uuq 115
Uup 116
117 Uuh
118 Uus
Uuo Uuo
The periodic table of elements is the organization depending on several criteria, distributes the various chemical elements according to certain characteristics.
Usually attributed to Dmitri Mendeleev table who ordered the items based on the manual variation of chemical properties, while Julius Lothar Meyer, working separately, conducted a system from the physical properties of atoms.
The discovery of elements[Edit]
While some elements such as gold (Au), silver (Ag), copper (Cu), lead (Pb) and mercury (Hg) were already known since antiquity, the first scientific discovery of an element occurred in the seventeenth century when the alchemist Henning Brand discovered phosphorus (P). In the eighteenth century met many new elements, the most important of which were gases, with the development of pneumatic chemistry:oxygen (O), hydrogen (H) and nitrogen (N). Also been consolidated in these years the new design element that led to Antoine Lavoisier to write his famous list of simple substances, which showed 33 elements. In the early nineteenth century, the application of the electric battery to the study of chemical phenomena led to the discovery of new elements such as alkali metals, alkaline earth, especially through the work of Humphry Davy. In 1830 already knew: 55 items. Subsequently, in mid-nineteenth century with the invention of the spectroscope, new elements were discovered, many of whom are appointed by the color of their characteristic spectral lines:cesium (Cs, Latin caes? us, blue), thallium (Tl, stem, green in color), rubidium (Rb, red, etc.).
The notion of element and the periodic properties [edit]
Logically, a necessary prerequisite to the construction of the periodic table was the discovery of a sufficient number of individual elements that make it possible to find any pattern in chemical behavior and properties. During the next 2 centuries, it acquired a great knowledge about these properties, as well as discovering many new elements. The word “element” comes from Greek science but the modern notion appeared throughout the seventeenth century, although there is no clear consensus regarding the process that led to its consolidation and widespread use. Some authors cite as precedent the phraseRobert Boyle in his famous book “The Skeptical Chymist,” where elements called “certain primitive and simple bodies are not formed by other bodies, or each other, and are the ingredients that make up immediately, and that are resolved in Ultimately all perfectly mixed bodies. Actually, that phrase appears in the context of criticism of Robert Boe to the four Aristotelian elements. Throughout the eighteenth century, collected many tables a new way of understanding the chemical composition, which is clearly stated by Lavoisier in his “Elementary Treatise of Chemistry”. This led to differentiate first substances to the hitherto known chemical elements were, what their properties and how to isolate them.
The discovery of a large number of new elements, and the study of their properties, revealed some similarities between them, raising the interest of chemists for some type of classification.
The atomic weights [edit]
In the early nineteenth century, John Dalton (1766-1844) developed a new conception of atomism, which came thanks to his studies of meteorological and atmospheric gases. His main contribution was the formulation of a “chemical atomism” that allowed integrating the newly defined element by Antoine Lavoisier (1743-1794) and ponderal laws of chemistry (definite proportions, multiple proportions, proportions recíprocas). Dalton used the knowledge of the proportions of the reacting substances of his time and made some assumptions about the way atoms combined them. Established as a reference unit mass of a hydrogen atom (although others were suggested in those years) and told the rest of the values at this unit, so he could build a system of relative atomic masses. For example, in the case of oxygen, Dalton started from the assumption that water is a binary compound consisting of one atom of hydrogen and oxygen. I had no way to check this point, so he had to accept this possibility as a priori hypothesis. Dalton knew that 1 part of hydrogen combines with 7 parts (8 today would claim) of oxygen to produce water. Therefore, if the combination occurred atom by atom, ie a hydrogen atom combined with a tungsten atomThe relationship between the masses of these atoms should be 1:7 (or 1:8 would be calculated at present). The result was the first table of relative atomic masses (or atomic weight Dalton called them) which was subsequently modified and developed in subsequent years. The uncertainties mentioned above led to a series of controversies and disparities in the formulas and atomic weights that only begin to overcome, though not entirely, with the congress in Karlsruhe in 1860.
Metals, nonmetals and semi-metals [edit]
The first classification of known elements was proposed by Antoine Lavoisier, who proposed that the elements are classified into metals, nonmetalsand metalloids or transition metals. Although very practical and functional yet modern periodic table, was rejected because there were many differences in physical and chemical properties.
Döbereiner Triads [edit]
One of the first attempts to group items of similar properties and relate it to the atomic weights due to the German chemist Johann Wolfgang Döbereiner (1780-1849) who in 1817 showed that there was the striking similarity between the properties of certain groups of three elements, with a gradual change from first to last. Later (1827) noted the existence of other groups of three elements which gave the same ratio (chlorine, bromine and iodine, sulfur, selenium and tellurium, lithium, sodium and potassium).
Triads Triads Döbereiner Döbereiner
Lithium LiCl
LiOHCalcium CaCl2
CaSO 4sulfur H 2CaSO4AzufreH2S
SO2
NaCl Sodium
Strontium NaOH SrCl 2
SrSO 4Selenium H 2SrSO4SelenioH2Se
SeO2
Potassium KCl
KOH Barium BaCl 2
BaSO 4TelluriumH 2BaSO4TeluroH2Te
TeO2
These groups of three elements are called triads and by 1850 had already found about 20, indicating a certain regularity between the chemical elements.
Döbereiner attempt to relate the chemical properties of these elements (and compounds) with the atomic weights, having a great analogy between them, and a gradual change from first to last.
In their ranking of the triads (grouping of three elements) Döbereiner explained that the average atomic weight of the weights of the extreme elements is similar to the atomic weight of element in between. For example, the triad Chlorine, Bromine, Iodine atomic weights are respectively 36, 80 and 127, if we add 36 + 127 and divide by two, we get 81, which is about 80, and if we look at our periodic table the element with the atomic weight of approximately 80 is bromine match making an apparent order of triads.
Vis tellurique of Chancourtois [edit]
In 1864 he built a propeller Chancourtois paper on which were arranged by atomic weight elements known, wound on a vertical cylinder. He was concerned that the points were separated about 16 units. Similar elements were virtually on the same generatrix, indicating a certain frequency, but its plot seemed very complicated and received little attention.
Law of octaves of Newlands [edit]
In 1864, the English chemist John Alexander Reina Newlands advised the Royal College of Chemistryhis observation that the order of the elements in increasing order of their atomic weights (ignoring hydrogen), the eighth element from any other had very similar properties to the first. At this time, are called noble gases had not yet been discovered.
Law of octaves of Newlands Act of octaves of Newlands
1 2 3 4 5 6 7 1 2 3 4 5 6 7
Li Li 6.9 Na 23.0 K 23.0 K 39.0 Na 6.9 Be Be 9.0 Mg 9.0 Ca 24.3 Mg 24.3 Ca 40.0 B 10.8 to B 10, 8 At 27.0C 12.0 If If C 12.0 N 28.1 N 14.0 P 14.0 P 16.0 S 31.0 W 32.1 W 16.0 S 19.0 F 6.9 Na Li Cl 23 , 0 K 39.0 Ca 24.3 Mg 9.0 Be 40.0 B 10.8 to 27.0 C 12.0 If 28.1 N 31.0 O 14.0 P 16.0 S 32.1 Cl 19.0 F 35.5
This law showed a certain ordering of the elements into families (groups), with properties very similar to each other and in periods, consisting of eight elements whose properties were varied progressively.
The name is based on the octaves of Newlands intention to relate these properties to what exists in the scale of musical notes, so he gave his discovery the name of law of octaves.
As calcium from left to break this rule, this arrangement was not appreciated by the scientific community that scorned and ridiculed, until 23 years later was recognized by the Royal Society, which gave its highest award, Newlands, the Medal Davy.
Mendeleyev’s periodic table [edit]
Main article: Mendeleyev’s periodic table
The periodic table of elements was proposed by Dimitri Mendeleev and Julius Lothar Meyer, who, working separately, prepared a sort of all 64 known elements, based on the variation of chemical properties (Mendeleev) and physical (Meyer) with variation of their atomic masses. Unlike what was supposed Newlands, in Mendeleev’s periodic table periods (diagonal and oblique lines) were not always the same length, but along the same there was a gradual variation of properties, so that the elements of the same group or family were consistent in different periods. This table was published in 1869, based on the properties of elements are periodic function of their atomic weights.
The notion of atomic and quantum mechanics [edit]
Mendeleyev’s periodic table showed some irregularities and problems. In the decades after he had to integrate the findings of the noble gases, the “rare earths and radioactive elements. An additional problem was that there were irregularities in reconciling the sort order of increasing atomic weight and the group of families with common chemical properties. Examples of this difficulty is found in couples tellurium-iodine, argon-potassium and cobalt-nickel, which is necessary to alter the criterion of increasing atomic weights for the cluster in families with similar chemical properties. For some time, this issue could not be satisfactorily resolved until Henry Moseley (1867-1919) conducted a study on X-ray spectra in 1913. Moseley found that when plotting the square root of the frequency of radiation depending on the sequence number in the periodic system is obtained a straight line, which allowed to think that this order was not accidental but reflects some property of the atomic structure. Today we know that this property is theatomic number (Z) or number of positive charges in the nucleus. The currently accepted explanation of the “periodic law” discovered by chemists at mid-century theoretical developments emerged after produced in the first third of the twentieth century. In the first third of the twentieth century was built quantum mechanics of Mendeleyev’s periodic table showed some irregularities and problems. In the decades after he had to integrate the findings of the noble gases, the “rare earths and radioactive elements. An additional problem was that there were irregularities in reconciling the sort order of increasing atomic weight and the group of families with common chemical properties. Examples of this difficulty is found in couples tellurium-iodine, argon-potassium and cobalt-nickel, which is necessary to alter the standard of weights atomics for increasing the grouping into families with similar chemical properties. For some time, this issue could not be satisfactorily resolved until Henry Moseley (1867-1919) conducted a study on X-ray spectra in 1913. Moseley found that when plotting the square root of the frequency of radiation depending on the sequence number in the periodic system is obtained a straight line, which allowed to think that this order was not accidental but reflects some property of the atomic structure. Today we know that this property is the atomic number (Z) or number of positive charges in the nucleus. The currently accepted explanation of the “periodic law” discovered by chemists at mid-century theoretical developments emerged after produced in the first third of the twentieth century. In the first third of the twentieth century was built quantum mechanics. Thanks to this research and subsequent developments, is now accepted that the ordering of the elements in the periodic table is related to the electronic structure of atoms of different elements, from which we can predict their different chemical properties.
Grupo101112131415161718 Grupo101112131415161718
I II III IV V VI VII VIII I II III IV V VI VII VIII
Period Period
1
2
He He
3
Li 4
Be 5
6
7
8
9
10
Ne Ne
11
Na 12
Mg 13
At 14
If 15
16
17
CL 18
Ar Ar
19
20
CA 21
SC 22
Ti 23
24
Cr 25
Mn 26
Fe 27
Co 28
Ni 29
Cu 30
Zn 31
Ga 32
Ge 33
As 34
SE 35
BR 36
Kr Kr
37
Rb 38
SR 39
40
Zr 41
Nb 42
Mo 43
TC 44
Ru 45
Rh 46
Pd 47
Ag 48
CD 49
In 50
Sn 51
SB 52
TE 53
54
Xe Xe
55
56 Cs
Ba * 72
73 Hf
Ta 74
75
Re 76
Os 77
Go78
Pt 79
Au 80
Hg 81
Tl 82
Pb 83
Bi 84
Po 85
At 86
Rn Rn
87
FR 88
Ra ** 104
Rf105
106 Db
Sg 107
Bh 108
Hs 109
MT 110
111 Ds
112 Rg
113 Uub
114 Uut
Uuq 115
Uup 116
117 Uuh
Uus118
Uuo Uuo
Lanthanides * 57
The 58th
Ce 59
PR 60
Nd 61
Pm 62
SM 63
Eu 64
Gd 65
Tb 66
67 Dy
Ho 68
Er 69
TM 70
71 Yb
Lu Lu
Actinides ** 89
AC 90
Th 91
Pa 92
93
Np 94
Pu 95
Am 96
Cm 97
Bk 98
99 Cf
It is 100
FM 101
Md 102
No 103
Lr Lr
AlcalinosAlcalinotérreosLantánidosActínidosMetales transition transition AlcalinosAlcalinotérreosLantánidosActínidosMetales
PMetaloidesNo block metals noble metalesHalógenosGasesPMetaloidesNo block metals noble metalesHalógenosGases
Groups [edit]
A vertical column of the Periodic Table are called groups. All items belonging to a group have the same valence, and therefore have similar characteristics or properties among themselves. For example the elements in Group IA have valence 1 (one electron in its latest energy level) and all tend to lose that electron to the positive ions bind as +1. Items in the last group on the right are the noble gases, which have their last full energy level (octet rule) and therefore are all extremely non-reactive.
The groups of the Periodic Table, numbered from left to right are:
Group 1 (IA): the alkali metals
Group 2 (IIA): the alkaline earth metals
Group 3 to Group 12: the transition metals, noble metals and metals meek
Group 13 (IIIA): earth
Group 14 (IVA): carbonoideos
Group 15 (VA): nitrogenoideos
Group 16 (VIA): the chalcogens or Chalcogen
Group 17 (VIIA): the halogens
Group 18 (VIIIA) Noble Gas
Periods [edit]
Main article: Periods of the periodic table
The horizontal rows of the Periodic Table are called periods. Unlike as in the case of groups of the periodic table, the elements of the same row have different properties but similar masses: all elements of a period have the same number of orbitals. Following this rule, each item is placed according to their electron configuration. The first period has only two members:hydrogen and helium, both have only the 1s orbital.
The periodic table consists of 7 periods:
· Period 1
· Period 2
· Period 3
· Period 4
· Period 5
· Period 6
· Period 7
The table also is divided into four groups, s, p, d, f, which are located in the sdp order from left to right, and f lanthanides and actinides, this depends on the termination letter on the elements of this group as the principle of Aufban.