元素周期表和元素周期律是中学化学中很重要的内容,既是教学中的重点,也是高考的热点,确定元素在周期表中的位置是难点,学生感到无从下手,现归纳如下: 一、结构简图法本方法常用于原子序数小于18号元素或 The periodic table of the elements and the periodicity of the elements are very important contents in the middle school chemistry. It is not only the key point in teaching, but also the hot spot of the college entrance examination. Determining the position of the elements in the periodic table is a difficult point. Students feel unable to start. They are summarized as follows: I. Structure Schematic methods are often used for elements with atomic number less than 18 or