在中学化学教学中,经常遇到“化合价”这个概念,到底什么叫化合价?旧初中化学,旧高中化学,旧普通化学各有一套定义,它们既有联系,也有区别,这是根据学生学习程度的不同,确定深浅不同的内容要求而提出的,但是也必须看到,在未发全国统 In middle school chemistry teaching, often encounter the concept of “valence” in the end what is the valence? The old junior high school chemistry, the old high school chemistry, the old common chemistry each have a set of definitions, which are both linked, there are differences, which is based on the degree of student learning Of the different shades of content to determine the content requirements put forward, but must also see that in the absence of the national system