考点5碱金属元素（Test site 5 alkali metal elements）.docVIP

考点5碱金属元素（Test site 5 alkali metal elements） Test site 5 alkali metal elements 1. review the key points Comparison of atomic structure and physical properties of alkali metal elements, the chemical properties of alkali metal, steps of flame reaction experiment; Atomic nucleus outside electron arrangement; alkali metal element; similarity; recurrence 2. difficulties focus (1) the chemical properties of alkali metal elements: 1) similarity: the structural similarity of the basic metal elements determines the similarity of the properties of lithium, sodium, potassium, rubidium and cesium, and alkali metals are strong reducing agents, which are lively in nature. Specific performance in the can, and water, dilute acid solution containing reaction generated (for alkali metal ion compounds); they are the corresponding oxide hydrate alkali; 2) change: with the increase of atomic number and electron layers increases, the atomic radius gradually, gradually losing electrons easily, reducing crescendo, decided their change in the nature of. Specific performance: 1, and the reaction products become more and more intense, more and more complex, and the reaction has become increasingly intense, with the enhancement of the nuclear charge, the high alkaline oxide hydrate corresponding enhancement:; (2) the experiment is how to preserve the lithium, sodium and potassium are: active metal, easy oxidation and even cause combustion, they can react with water to produce hydrogen, water solution and alcohol solution, is flammable and explosive substances, store them to ensure that no contact with air and water; and because their density is small, so lithium can only be saved in liquid paraffin or sealed in paraffin wax, and the preservation of sodium and potassium in kerosene; (3) preparation of alkali metal and metal is mainly used method of electrolysis of molten metal because of chloride production; soluble salt is not easy to separate, and when the electrolytic reaction, therefore gene