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.
Hydrolysis involves the reaction of water with another compound.Hydrolysis is the process in which the bond breaks due to addition of water whereas in hydration there is just addition of water, the molecule doesn’t break down.
climate
Changes in the composition of the atmosphere have caused gradual changes in earth's <u>climate</u> throughout history, causing changes in plant and animal life that contributed to mass extinctions.
The following are some of the reasons:
- UV light
- climate
- pollutants
- hydrofluorocarbons
heat
- The surface of the Earth warms up as sunlight strikes it.
- Surface-emitted infrared light is absorbed in the atmosphere and transformed into heat.
- The temperature close to the surface rises as a result of this heat being trapped in the atmosphere.
<h3>UV light:</h3>
- indirect impacts of climate change on UV radiation from the surface.
- By changing the concentrations of ozone, UV-absorbing tropospheric gases, aerosols, and clouds in the atmosphere, climate change may have indirectly affected UV radiation levels in the past.
- These influences are probably going to persist in the future.
<h3>climate:</h3>
- People are at risk from food and water shortages, greater flooding, high heat, an increase in disease, and economic loss due to climate change.
- Conflict and human migration are potential outcomes.
- Climate change is the top hazard to world health in the twenty-first century, according to the World Health Organization (WHO).
<h3>pollutants:</h3>
- these are also resulting in the increase of temperature of the Earth and is also damaging ozone layer.
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Etaphase is a stage during the process of cell division (mitosis or meiosis). Usually, individual chromosomes cannot be observed in the cell nucleus. However, during metaphase of mitosis or meiosis the chromosomes condense and become distinguishable as they align in the center of the dividing cell.
Answer:
They contain atoms that combine together to form molecules. In multicellular organisms, such as animals, molecules can interact to form cells that combine to form tissues, which make up organs. ... All atoms contain protons, electrons, and neutrons.
