The knowledge of elements and their compounds is the basis and skeleton of middle school chemistry knowledge, and the knowledge of elements and their compounds is the basis of other chemistry knowledge. Many contents of elements and their compounds are closely related to the basic theory of chemistry. Although the content of elements and their compounds has decreased after the new curriculum reform, the college entrance examination has strengthened the combination of element knowledge with basic concepts and theories, and the requirements for the examination of element knowledge and its compounds have not decreased. The requirements of textbooks and outlines are relatively simple, but the actual requirements of the college entrance examination are not. At the same time, this part of knowledge is complex, fragmented and scattered, and there are many things to remember, so it is difficult for students to master and use it systematically. So how can we properly expand and grasp the appropriate degree? In view of the characteristics of this topic with many knowledge points, it is the correct learning method to grasp it with basic theories and concepts.

First, strengthen memory under the guidance of basic concepts and theories.

Many knowledge points of elements and their compounds are closely related to the basic concepts and theories of chemistry. When learning, you can use chemical concepts and theories to command and master the knowledge of elements and compounds, without rote learning. Based on the periodic law of elements, the properties of other elements and other compounds are controlled by the properties of representative elements of the same main group, such as halogen properties. On the basis of mastering the properties of chlorine and its compounds, the properties of other halogen elements and their compounds are deduced by using the similarity and gradient of the properties of the same main group elements. For example, according to the metal activity sequence table and nonmetal activity sequence, it can be inferred whether the substitution reaction occurs or not.