New changes periodic table elements

Atomic mass of 10 elements in the periodic table system includes hydrogen, lithium, carbon, nitrogen, oxygen, silicon, sulfur, chlorine and thallium are known in the literature and textbooks will be changed.

TS. Michael Wieser at the University of Calgary and was secretary of the committee on atomic weights and associations of Chemistry and Applied Chemistry international (IUPAC), said more than 150 years, we still believe that the volume of raw e of the elements are constant, but his research and his colleagues showed that these values change in a certain range.


Modern analytical techniques to determine atomic weights more accurately, small changes in volume atoms is of great significance in research and industry.

For example, the accuracy of the measurement of carbon isotope content of direct effect to the determination of the purity and source of food. Similarly, precise measurements of isotopes of nitrogen, chlorine ... to help search for causes of water pollution.

In sports, it was discovered that athletes use testosterone doping and by measuring levels of carbon isotopes. Dr. Weiser said, "so that our atomic mass can decipher the historical origins of an element in nature."

Atomic mass of 10 elements will be in a range, upper and lower limits, meaning that it is not fixed but change as previously thought. For example, the amount of sulfur still today is considered to be 32.065 shall be in the range of 32.059 to 32.076, depending on the compounds that are present.

Some elements such as fluorine, sodium, aluminum and gold have atomic weights almost fixed, because only small changes from Friday digits after the decimal point.

IUPAC deputy director, Dr. Fabienne Meyers said that the results of this study have important implications, but it will again arise from the challenge of teaching students to perform mathematical chemistry.

Currently scientists in the fields of physics, environment, chemistry and geography at the University of Calgary are using the results of research to elucidate the origin of meteorites, to determine the source of air pollution , water and study the existence of carbon dioxide in the earth.

The work was conducted from 1985 to 2010. IUPAC has accepted the results and will use this data to international standards.