Julius lothar meyer in chemistry

He then undertook an investigation into a key medical-chemical problem that was poorly understood at the time: the deadly effect of carbon monoxide on the blood. That work earned him a second Ph. Finally, Meyer considered himself ready to teach.

Julius lothar meyer in chemistry

He continued, however, to attend conferences and stay up to date on new research developments relevant to his interests. The Karlsruhe Congress ofa large scientific conference, proved especially important. The conference was devoted to the emerging field of the classification of chemical elements. At the time, it was recognized that matter was composed of different elements that had different atomic structures, but there was no organized way of dealing with the diversity that the physical forms of matter presented.

Meyer's book contained something new: a table of elements ordered by atomic weight the weight of all the atomic particles a molecule of an element contains, now known as relative atomic mass and by valence the tendency of particles that are part of an element to combine with those of other elements. Using these principles, Meyer left a blank space in his table for an element that was not yet known but that, he guessed correctly, remained to be discovered it has since been shown to be germanium, with an atomic weight of the predicted His table covered only 28 common elements, but it included the important insight that they could be grouped into families according to their valences.

Building on previous studies by G. Magnus, he was able to demonstrate in that oxygen absorption by blood in the lungs occurs independently of pressure. This suggested to him that some possibly loose chemical linkage occurred. When he turned his julius lothar meyer in chemistry to carbon monoxide poisoning, Meyer demonstrated a similar chemical linkage between that gas and a constituent of the blood.

Further, he found that the amounts of oxygen and carbon monoxide taken up by the blood were in a simple molecular ratio, the carbon monoxide being able to expel volume for volume the oxygen already in the blood. This suggested to him that the same constituent of blood reacted with both gases. His preliminary searches for this constituent were unsuccessful.

Hemoglobin was discovered by Hoppe-Seyler in ByMeyer had completed the manuscript of Moderne Theorienincluding a table of twenty-eight elements in order of increasing atomic weight. Meyer saw J. Such a quantitative relationship suggested to some the likelihood that atoms were not the ultimate building blocks of nature—that they were composite, with the differences in weight of successive members of triads representing weights of more fundamental units.

The common increment of 14 in these weights suggested that organic radicals may well hold the clue to the nature of the internal structure of inorganic atoms. Similar ideas were independently developed by Dumas, who spoke about them to the British Association for the Advancement of Science in but did not publish them until GladstoneJ.

CookeW. Odlingand E. Lenssen No progress beyond the arithmetic comparisons of weights of similar elements was likely as long as no clear distinction was made between equivalent and atomic weights, and no path to the values of the latter was generally accepted. That clarification was achieved by Cannizzaro at Karlsruhe inand almost immediately further relations between the elements became apparent.

In A. He then appends a tabulation see Figure 1 of twenty-eight elements, arranged according to increasing atomic weight, in six families that have valences of 4, 3, 2, 1, 1, and 2, respectively. Thus the integral stepwise change in valence as atomic weight increases was in print by A relation between families, and hence between dissimilar yet neighboring elements, was clearly established.

Meyer remained interested also in constant increments within families and left a space for an as yet undiscovered element between silicon and tin, clearly indicating its probable atomic weight to be It differs from the table mainly by the addition of twenty-four elements and nine families. These were the B-subgroups, the characteristics of which Meyer later claimed to have discovered independently.

Hydrogen, boron, and indium are not in the table, and aluminum appears in both column 3. Boron, indium, and aluminum properly belong in a family between columns 7 and 8. Meyer placed lead Pb correctly in column 8, while Mendeleev put it with calcium, strontium, and barium. Both Meyer and Mendeleev emphasized that there is a periodic variation, a succession of maxima and minima, in several physical and chemical properties when they are examined as functions of atomic weight.

Meyer began this paper with the assertion that it is julius lothar meyer in chemistry improbable that the chemical elements are absolutely undecomposable and referred to the ideas of Prout, Pettenkofer, and Dumas. As for the gaps in the table, he suggested that they would be filled through careful redeterminations of the atomic weights of known elements or through the discovery of new ones.

The significance of atomic weights in the demonstration of chemical periodicity, and the suspicion that some atomic weights were not accurate, led Meyer and Seubert to examine critically and to recalculate all atomic weights then considered important. Their study was published in All atomic weights were referred to the standard of unity for the atomic weight of hydrogen, a standard Meyer championed.

In the newly created International. In organic structural theory Meyer became involved in discussions of the structure of benzene. Only one. He suggested that each carbon used only three of its four affinities, leaving one valence unsatisfied. The unused valences point to the center of the ring. Meyer studied a number of benzene substitution reactions, particularly the nitration of benzene and its derivatives.

His father died while he was young, and so his mother moved the family km to St. In his adult life he was a brilliant scientist, rising quickly in academic circles. Mendeleev discovered the periodic table or Periodic System, as he called it while attempting to organise the elements in February of He did so by writing the properties of the elements on pieces of card and arranging and rearranging them until he realised that, by putting them in order of increasing atomic weight, certain types of element regularly occurred.

For example, a reactive non-metal was directly followed by a very reactive light metal and then a less reactive light metal. Initially, the table had similar elements in horizontal rows, but he soon changed them to fit in vertical columns, as we see today. Not only did Mendeleev arrange the elements in the correct way, but if an element appeared to be in the wrong place due to its atomic weight, he moved it to where it fitted with the pattern he had discovered.

For example, iodine and tellurium should be the other way around, based on atomic weights, but Mendeleev saw that iodine was very similar to the rest of the halogens fluorine, chlorine, bromineand tellurium similar to the group 6 elements oxygen, sulphur, seleniumso he swapped them over. He even predicted the properties of five of these elements and their compounds.

The table below shows the example of Gallium, which Mendeleev called eka-aluminium, because it was the element after aluminium. This gave the table the periodicity of 8 which we know, rather than 7 as it had previously been. Mendeleev never received a Nobel Prize for his work, but element was named Mendelevium after him, an even rarer distinction.

Formula Ea 2 O 3density 5. Soluble in both acids and alkalis. Formula Ga 2 O 3density 5. A commemorative stamp showing Mendeleev and some of his original notes about the Periodic Table. The periodic table was arranged by atomic mass, and this nearly always gives the same order as the atomic number. Mendeleev had seen that they needed to be swapped around, but it was Moseley that finally determined why.

He fired the newly-developed X-ray gun at samples of the elements, and measured the wavelength of X-rays given. He used this to calculate the frequency and found that when the square root of this frequency was plotted against atomic number, the graph showed a perfect straight line. Download as PDF Printable version. In other projects. Wikimedia Commons Wikidata item.

German physician and chemist — For the German footballer, see Lothar Meyer footballer. VarelDuchy of Oldenburg. Career [ edit ]. Periodic table [ edit ]. Table of Meyer, [ edit ]. Personal life [ edit ]. Tribute [ edit ]. See also [ edit ]. Notes [ edit ]. Cambridge University Press. Rocke Ohio State University Press.