Alkalis that did not melt easily were called “alkaline earths.” The elements of group 2 are collectively referred to as the alkaline earth metals, a name that originated in the Middle Ages, when an “earth” was defined as a substance that did not melt and was not transformed by fire. For example, because potassium is required for plant growth, its compounds are used in fertilizers, and lithium salts are used to treat manic-depressive, or bipolar, disorders. Other compounds of the alkali metals are important in biology. Sodium salts such as common table salt (NaCl), baking soda (NaHCO 3), soda ash (Na 2CO 3), and caustic soda (NaOH) are important industrial chemicals. As a result, they have a strong tendency to lose their single valence electron to form compounds in the +1 oxidation state, producing the EX monohalides and the E 2O oxides.īecause they are so reactive, pure group 1 elements are powerful reducing agents that are used in lithium batteries and cardiac pacemakers. The alkali metals have ns 1 valence electron configurations and the lowest electronegativity of any group hence they are often referred to as being electropositive elements. It is so radioactive that studying its chemistry is very difficult. The heaviest element (francium) was not discovered until 1939. ![]() However, the group 1 elements, like the group 2 elements, become less reactive with air or water as their atomic number decreases. The potassium burst into flames as soon as it was produced because it reacts readily with oxygen at the higher temperature. Potassium and sodium were first isolated in 1807 by the British chemist Sir Humphry Davy (1778–1829) by passing an electrical current through molten samples of potash (K 2CO 3) and soda ash (Na 2CO 3). Although oxides of both group 1 and group 2 elements were obtained from wood ashes, the alkali metals had lower melting points. ![]() ![]() Alkali (from the Arabic al-qili, meaning “ashes of the saltwort plant from salt marshes”) was a general term for substances derived from wood ashes, all of which possessed a bitter taste and were able to neutralize acids. The elements of group 1 are called the alkali metals.
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