A、B、C、D、E四种元素,它们原子的核电荷数均小于18,且依次递增,A原子核内仅有一个质子;B原子的电子总数与D原子的最外层电子数相等;A原子与B原子的最外层电子数之和与C原子的最外层电子数相等;D的最外层电子数是次外层电子数的3倍;E的单质是用途最广泛的半导体材料。试推断它们各是什么元素并回答下列问题:(1)写出它们的元素符号:A________,B________,C________,D________,E________。(2)B、C、D的气态氢化物的稳定性由大到小的顺序为__________(根据你听到的对话内容回答问题:
M: Excuse me, but how can I get to the History Museum, please?
W: Just over there beside the bookstore.
Q: What is the man doing?
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A.Asking the way.
B.Buying a book.
C.Going to work.