第三周期元素中，基态原子轨道表示式中存在着空轨道的元素有（   ）种。

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SQL Error: select id,body,options from ***_enewstiku_ where sourceid='21626' and id < 1882859 and id<>'1882859' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='21626' and id > 1882859 and id<>'1882859' order by id asc limit 5