石灰氮（CaCN2）是一种绿色的农药和化肥，可用作除草剂、杀菌剂_爱下问搜题

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问题选择题

石灰氮（CaCN₂）是一种绿色的农药和化肥，可用作除草剂、杀菌剂、杀虫剂和棉花脱叶剂，其可由CaC₂（离子化合物）与N₂反应制得。下列各项表达中不正确的是（　　）

A．C₂^2-的电子式为

B．N₂的结构式为N≡N

C．1 mol CN₂^2-所含的电子总数为22 mol

D．Ca²^＋的结构示意图为

答案

答案：D

1个C₂^2-中含有10个电子，碳原子之间形成3对共用电子对，A项正确；N₂分子中含有叁键，B项正确；1个CN₂^2-中含有的电子总数为6＋7×2＋2＝22，C项正确；D中Ca²^＋的质子数是20，错误。

完形填空

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Spring approaching, children   48  to make flower baskets for room decoration. During the lunch time, a girl came hurrying to me. “Come to see Mary’s basket,” she said   49 . “You’ll never believe it!” I   50  my breath at its beauty, for it couldn’t have been the work from a child that   51 .
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A．introducing

判断题

机动车信号灯红灯亮时，即使右侧没有行人或其他障碍物，也禁止右转弯的车辆通行。