试题与答案

面额100元的新版人民币，其正面左下方的数字“l00”．采用了光变色防伪油墨印刷

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题型：选择题

题目：

面额100元的新版人民币，其正面左下方的数字“l00”．采用了光变色防伪油墨印刷．防伪油墨中含有氟化镁（MgF2），其中F的化合价为-l，则镁元素的化合价为（　　）

A．+1

B．+2

C．+3

D．+4

答案：

根据化合物中元素化合价的代数和为0，氟化镁的化合价为MgF2，其中F的化合价为-l，则镁元素的化合价为0-（-1）×2=+2．

故选B．

考点：化合价的求法
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