烷烃与卤素反应的活性,叔氢>仲氢>伯氢;F_2>Cl_2>Br_2>I_2(氟代太剧烈,碘代难发生,氯代溴代较适中,氯代又比溴代易进行)。反应的选择性,Br_2>Cl_2 在教学中如何使这些结论定量化,是目前教材改革的重要方面之一。根据个人的体会,以下几方面的内容应该充分揉合到教材中。 Alkane and halogen reaction activity, tertiary hydrogen> secondary hydrogen> primary hydrogen; F_2> Cl_2> Br_2> I_2 (fluoride is too violent, iodine is difficult to occur, chlorine bromine more moderate, chlorine and bromine easier to carry out) . The selectivity of the reaction and how Br_2> Cl_2 can quantify these conclusions in teaching are one of the important aspects of the textbook reform. According to personal experience, the following aspects should be fully integrated into the teaching materials.