问题标题：
熟练书写下面20个元素符号氢________、碳________、氮________、氧________、钠________、镁________、铝________、硅________、磷________、硫________、氯________、钾________、钙________、锰________、铁________、铜__
问题描述：
熟练书写下面20个元素符号
氢________、碳________、氮________、氧________、钠________、镁________、铝________、硅________、磷________、硫________、氯________、钾________、钙________、锰________、铁________、铜________、锌________、银________、碘________、汞________．
其中：H的含义________．C的含义________．3H的含义________．
傅远彬回答：
H C N O Na Mg Al Si &n...
