They are also capable of reacting quite vigorously to form hydrogen gas and strong caustic solutions.Rubidium is the 37th element in the periodic table and its symbol is ‘Rb’. They react most easily with the oxygen in the atmosphere and water vapour. They are highly ductile and conduct electricity without any trouble.Īll alkali metals have a very low melting point and the alloys of such alkali metals display even lower melting points. All alkali metals show a silver-like lustre, which makes them appear shiny. Most of these metals are easily soluble in water, which makes their extraction quite easy. Q: What are the properties of alkali metals?Īns: Alkali metals are highly reactive in nature, which is why they manifest themselves in combination with other elements, in nature. The element was not isolated in pure form until Davy produced a minute quantity by the electrolysis of lithium chloride. The name lithium comes from lithos, the Greek word for stony. In the year 1817 Swedish chemist Johan August Arfwedson discovered Lithium while analyzing the mineral petalite. The name sodium comes from the Italian soda, a term applied in the Middle Ages to all alkalis, potassium comes from the French ‘potasse’, a name used for the residue left in the evaporation of aqueous solutions derived from wood ashes. In October in the year 1807, the English chemist Sir Humphry Davy isolated potassium and later sodium. In ancient times, earlier people knew about alkali metal salts through the Old Testament which refers to a salt called ‘Neter’ (sodium carbonate), extracted from the ash of vegetable matter. Saltpetre (potassium nitrate) was used in gunpowder, which was invented in China around about the 9th century AD and had been introduced into Europe by the 13th century. Most of these compounds are ionic in nature. Potassium + chlorine → potassium chlorideĪll alkalis manifest themselves as a white solid in their compound form that is capable of being dissolved in water. Following chemical equations demonstrate some of the ways in which they react: How Do Alkali Metals React Otherwise?Īs alkali metals are the most reactive group of metals in the periodic table, each of these metals is capable of reacting with different elements to produce different results. Potassium + water → potassium hydroxide + hydrogenĪll elements in a particular group react in an analogous manner. Sodium + water → sodium hydroxide + hydrogenĢ Na(s) + 2 H 2O(l) → 2 NaOH (aq) + H 2(g) Lithium + water → lithium hydroxide + hydrogenĢ Li(s) + 2 H 2O(l) → 2 LiOH (aq) + H 2(g) The following chemical equations demonstrate how various metals react with water: Alkaline metals when reacting with water produce an alkaline solution, along with the release of hydrogen gas. Alkali Metals Reactivity with WaterĪlkali metals derive their classification because of the results of their reaction with water. As a conductor of heat and electricity, they are excellent. Upon being cut into two halves, we can observe that their surface is as shiny as any other metal but even after they are stored in oil, they undergo tarnishing. Therefore, if we decide to cut these metals, we will be able to do so, without much trouble. When it comes to the density of the metal, group one elements display a very low level of density of up to 1 gcm -3 which means that they can easily float on the surface of the water. The melting points of these elements are quite low, which is 180° Celsius in the case of Lithium, while it is 39° Celsius in the case of Rubidium. In order to prevent the elements from coming in contact with oxygen, they are stored in jars that contain oil. Caesium is the most metallic element in the group. As we move down the group, the atomic radius increases. They have the least nuclear charge in their respective periods. They have a strong tendency to donate their valence electron in the last shell to form strong ionic bonds. The general electronic configuration of elements of group 1 is ns 1. Included in Group 1 of the periodic table, the following are the alkali metals:
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