This means that they behave chemically as metals (although beryllium compounds are covalent) and lose the two valence electrons to form compounds in the +2 oxidation state. Radium was discovered in 1902 by Marie Curie (1867–1934 Nobel Prize in Chemistry 1903 and Nobel Prize in Chemistry 1911), who, with her husband, Pierre, isolated 120 mg of radium chloride from tons of residues from uranium mining.Īll the alkaline earth metals have ns 2 valence electron configurations, and all have electronegativities less than 1.6. As is the case with the alkali metals, the heaviest element, radium, is highly radioactive, making its size difficult to measure. Beryllium is relatively unreactive but forms many covalent compounds, whereas the other group members are much more reactive metals and form ionic compounds. Consistent with this trend, the properties of the lightest element-in this case, beryllium-tend to be different from those of its heavier congeners, the other members of the group. Recall that the trend in most groups is for the lightest member to have properties that are quite different from those of the heavier members. 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. Rubidium and cesium are extremely reactive and difficult to handle in the atmosphere when there is any water vapor present We can watch a video demonstration of the properties of lithium, sodium and potassium. 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. Alkalai metals with only a single s electron, and very low ionization energies can easily do this and thus are powerful reducing agents. Reducing agents are species that can lose an electron in a reaction. 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. 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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