Search results
Results From The WOW.Com Content Network
Alanine was first synthesized in 1850 when Adolph Strecker combined acetaldehyde and ammonia with hydrogen cyanide. [8] [9] [10] The amino acid was named Alanin in German, in reference to aldehyde, with the interfix-an-for ease of pronunciation, [11] the German ending -in used in chemical compounds being analogous to English -ine.
Toggle the table of contents. Alanine (data page) ... Chemical formula: C 3 H 7 N O 2 Molar mass: 89.1 g·mol −1
This is a list of chemical elements and their atomic properties, ordered by atomic number (Z).. Since valence electrons are not clearly defined for the d-block and f-block elements, there not being a clear point at which further ionisation becomes unprofitable, a purely formal definition as number of electrons in the outermost shell has been used.
A chemical element, often simply called an element, is a type of atom which has a specific number of protons in its atomic nucleus (i.e., a specific atomic number, or Z). [ 1 ] The definitive visualisation of all 118 elements is the periodic table of the elements , whose history along the principles of the periodic law was one of the founding ...
However, in real materials there are deviations from this in some metals where the unit cell is distorted in one direction but the structure still retains the hcp space group—remarkable all the elements have a ratio of lattice parameters c/a < 1.633 (best are Mg and Co and worst Be with c/a ~ 1.568).
The mass number is different for each isotope of a given chemical element, and the difference between the mass number and the atomic number Z gives the number of neutrons (N) in the nucleus: N = A − Z. [2] The mass number is written either after the element name or as a superscript to the left of an element's symbol.
Example: copper in terrestrial sources. Two isotopes are present: copper-63 (62.9) and copper-65 (64.9), in abundances 69% + 31%. The standard atomic weight (A r °(Cu)) for copper is the average, weighted by their natural abundance, and then divided by the atomic mass constant m u.
In his report on The Periodic Law of the Chemical Elements in 1869, the Russian chemist Dmitri Mendeleev predicted the existence of several unknown chemical elements, including one that would fill a gap in the carbon family, located between silicon and tin. [12] Because of its position in his periodic table, Mendeleev called it ekasilicon (Es ...