化合价的概念是十九世纪中叶引入化学领域的。经过一个多世纪的发展,在现代基础化学学科中,已扩大为几个不同的概念。对离子键来说,化合价可理解为元素的电价;对共价键来说,化合价可理解为元素的共价。从电子转移的角度来说,化合价又可理解为氧化数。因此什么是化合价?什么是氧化数?它们之间的联系和区别在什么地方?这对于我们化学教师应该明确地把它们分清楚,决不能含糊其词,在 The concept of valence was introduced into the chemical field in the middle of the nineteenth century. After more than a century of development, modern basic chemistry has expanded into several different concepts. For ionic bonds, valence is understood as the price of the element; for covalent bonds, the valence is understood as the covalentness of the element. From the standpoint of electron transfer, valence can also be understood as oxidation number. So what is a valence? What is an oxidation number? Where are the connections and differences between them? This should be clear to our chemistry teachers and they must not be vague.