The alkali metals are so reactive that they are never found in nature in elemental form. Although some of their ores are abundant, isolating them from their ores is somewhat difficult. For these reasons, the group 1 elements were unknown until the early 19th century, when Sir Humphry Davy first prepared sodium (Na) and potassium (K) by passing an electric current through molten alkalis. (The ashes produced by the combustion of wood are largely composed of potassium and sodium carbonate.) Lithium (Li) was discovered 10 years later when the Swedish chemist Johan Arfwedson was studying the composition of a new Brazilian mineral. Cesium (Cs) and rubidium (Rb) were not discovered until the 1860s, when Robert Bunsen conducted a systematic search for new elements. Known to chemistry students as the inventor of the Bunsen burner, Bunsen’s spectroscopic studies of ores showed sky blue and deep red emission lines that he attributed to two new elements, Cs and Rb, respectively. Francium (Fr) is found in only trace amounts in nature, so our knowledge of its chemistry is limited. All the isotopes of Fr have very short half-lives, in contrast to the other elements in group 1.
Answer:
Coke.
Explanation:
The distillation of coal tar can obtain aromatic compounds like benzene and toluene, and also phenolic compounds like phenol. Hence, the only option here that cannot be obtained from the distillation of coal tar is coke.
Hope this helped!
What effect does removing predators have on prey?
:It means that as they are removed the predators go hungry and they could become extinct.
Hope I helped!
The answer is c)11 because copper has 11 valence electrons
Answer:
I'm pretty sure its stimulus
