一、知识体系二、内容辅导1．熟记并理解各个概念的含义，能根据定义对某种现象作出物质性质或变化的判断。2．在初中阶段，尤其要掌握以下两种化学性质：1）化合价。要理解化合价的实质（元素的一定数目的原子相互化合的性质），了解化合价的确定方法（离子化合物中，元素化合 I. Knowledge System II. Content Coaching 1. Memorize and understand the meaning of each concept, according to the definition of a phenomenon to make a material nature or change judgments. 2. In the junior high school stage, in particular, we must grasp the following two chemical properties: 1) valence. To understand the nature of valence (the nature of a certain number of atoms in an element that interact with each other), understand how to determine valence (in ionic compounds, elemental combinations)