file:163钪、钇、镧系和锕系(下).flv file:156铬、锰副族(六).flv file:140氢和稀有气体(下).flv file:137卤素(九).flv file:91碱金属和碱土金属(三).flv file:88氧化还原反应和电化学(十二).flv