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:
droughts in California have become more common in California
Explanation:
Climate is weather over time which means that the first and the third one are just isolated incidents and the last answer choice shows climate but it doesn't show a change in climate
Answer:
The pellet fraction will be most radioactive because the heavy protein part of ghost will be present in the the pellet fraction.
Explanation:
supernatant can be defined as a liquid part that lies above the sediment of the centrifuge tube on the other hand pallet is a solid material present at the bottom end of the centrifuge tube.
As protein molecules in the given experiment is radio labelled that"s why the pellet fraction will be radio labeling part because the heavy protein molecules will be present in the pellet fraction.
Answer:
23dm
Explanation:
so you have to do 10g +13dm so the you have to times it by 3 three times