【单选题】A) He has just too many things to attend to. B) He has been overworked recently. C) He has a difficult decision to make. D) He has just quarreled with his girlfriend.
【简答题】(14分)已知A、B、C、D、E、F是短周期中的6种非金属元素,它们的原子序数依次增大。A元素是周期表中半径最小的元素, B原子的最外层上有4个电子;C与D在周期表中处于相邻的位置,D的阴离子和E的阳离子具有相同的电子层结构,两元素的单质反应,生成一种淡黄色的固体Y;F的L层电子数等于K、M两个电子层上电子数之和 (1)请写出元素符号: A B C D E F (2)画出F的阴离子的结构示意图 (...