一、氧族元素的命题规律分析硫及其化合物间的转化关系复杂,与氧化还原反应知识、化学计算、环境保护知识的综合考查是本单元的热点。特别是SO_2的性质。SO_3~(2-)、SO_4~(2-)的性质及检验,浓硫酸的性质等在高考命题中出现机率更大。从近年的高考来看,《氧族元素及环境保护》这部分内 I. Analysis of the Propositional Rule of Oxygen Elements The analysis of the transformation relationship between sulfur and its compounds is complex, and the comprehensive examination of knowledge of redox reactions, chemical calculations, and environmental protection knowledge is a hot spot in this unit. Especially the nature of SO_2. The properties and testing of SO_3~(2-), SO_4~(2-), and the nature of concentrated sulfuric acid are more likely to occur in college entrance examination propositions. From the college entrance examination in recent years, this part of the “oxygen elements and environmental protection”