Rubidium is denser than water and so sinks. This time the normal hydrogen flame is contaminated by potassium compounds and so is coloured lilac (a faintly bluish pink). Potassium behaves rather like sodium except that the reaction is faster and enough heat is given off to set light to the hydrogen. The colour is due to contamination of the normally blue hydrogen flame with sodium compounds. If the sodium becomes trapped on the side of the container, the hydrogen may catch fire to burn with an orange flame. The sodium moves because it is pushed around by the hydrogen which is given off during the reaction. A white trail of sodium hydroxide is seen in the water under the sodium, but this soon dissolves to give a colourless solution of sodium hydroxide. Sodium also floats on the surface, but enough heat is given off to melt the sodium (sodium has a lower melting point than lithium and the reaction produces heat faster) and it melts almost at once to form a small silvery ball that dashes around the surface. The reaction generates heat too slowly and lithium's melting point is too high for it to melt (see sodium below). It gradually reacts and disappears, forming a colourless solution of lithium hydroxide. Lithium's density is only about half that of water so it floats on the surface, gently fizzing and giving off hydrogen. In each of the following descriptions, I am assuming a very small bit of the metal is dropped into water in a fairly large container. This equation applies to any of these metals and water - just replace the X by the symbol you want. In each case, a solution of the metal hydroxide is produced together with hydrogen gas. It uses these reactions to explore the trend in reactivity in Group 1.Īll of these metals react vigorously or even explosively with cold water. This page looks at the reactions of the Group 1 elements - lithium, sodium, potassium, rubidium and caesium - with water. REACTIONS OF THE GROUP 1 ELEMENTS WITH WATER Now compare the reactivity of calcium and magnesium with water.Reactions of the Group 1 elements with water Watch the videos above and compare the reactivity of sodium and potassium with water. Notice how reactivity of metals increases as we go down a group. Potassium reacts faster than sodium to produce hydrogen gas.Įlements in group 2 also react with water to form hydrogen gas but are not as reactive as group 1 elements. Sodium reacts slowly with water to produce hydrogen gas. Click on the blue writing below to see the reactions. These metals react with water to produce hydrogen gas. These metals react readily with other compounds and elements to give away some of their outer shell (valence) electrons. AllĮlements in group 1 are very reactive metals, with the exception of hydrogen Elements in the same group display similar chemical properties and trends emerge as we go along a period and down a group.Īll elements in a particular group share similar chemical properties. The table is divided into groups(columns) and periods(rows). The modern periodic table has elements arranged in order of electronicĬonfiguration. Recognise that elements can be grouped together according to atomic mass. Mendelev was a Russian scientist who was first to The periodic table is a way of organizing known elements into groups with
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