问题 填空题

氮可以形成多种离子,如N3,NH2,N3,NH4+,N2H5+,N2H62+等,已知N2H5+

与N2H62+是由中性分子结合质子形成的,类似于NH4+,因此有类似于 NH4+的性质。

⑴写出N2H62+在碱性溶液中反应的离子方程式                               

⑵NH2的电子式为               。      

⑶N3        个电子。

⑷写出二种由多个原子组成的含有与N3电子数相同的物质的化学式         

⑸等电子数的微粒往往具有相似的结构,试预测N3的构型                   

⑹据报道,美国科学家卡尔·克里斯特于1998年11月合成了一种名为“N5”的物质,由于其具有极强的爆炸性,又称为“盐粒炸弹”。迄今为止,人们对它的结构尚不清楚,只知道“N5”实际上是带正电荷的分子碎片,其结构是对称的,5个N排成V形。如果5个N结合后都达到8电子结构,且含有2个N≡N键。则“N5”分子碎片所带电荷是           

答案

⑴N2H62++2OH=N2H4+2H2O     ⑵     ⑶22 

⑷N2O   CO2  CNO   BeF2  CaH2  C3H4等    ⑸直线型      ⑹一个单位正电荷

题目分析:⑴NH4+与碱反应的离子方程式为:NH4++OH-=NH3+H2O。由于NH4+与N2H62+结构相似,所以N2H62+在碱性溶液中反应的离子方程式为N2H62++2OH=N2H4+2H2O。⑵NH2是NH3失去质子后形成的。所以NH2的电子式为。⑶N是7号元素,所以N3有22个电子。⑷由多个原子组成的含有与N3电子数相同的物质有N2O 、 CO2CNO、BeF2CaH2、C3H4等。⑸等电子数的微粒往往具有相似的结构,由于CO2与N3是等电子体。所以N3的构型是直线型。⑹其结构是对称的,5个N排成V形。如果5个N结合后都达到8电子结构,且含有2个N≡N键。其结构为“N5”分子碎片所带电荷是一个单位正电荷。

问答题 案例分析题
单项选择题

Electronic mail has become an extremely important and popular means of communication.
The convenience and efficiency of electronic mail are threatened by the extremely rapid growth in the volume of unsolicited commercial electronic mail. Unsolicited commercial electronic mail is currently estimated to account for over half of all electronic mail traffic, up from an estimated 7 percent in 2001, and the volume continues to rise. Most of these messages are fraudulent or deceptive in one or more respects.
The receipt of unsolicited commercial electronic mail may result in costs to recipients who cannot refuse to accept such mail and who incur costs for the storage of such mail, or for the time spent accessing, reviewing, and discarding such mail, or for both. The receipt of a large number of unwanted messages also decreases the convenience of electronic mail and creates a risk that wanted electronic mail messages, both commercial and noncommercial, will be lost, overlooked, or discarded amidst the larger volume of unwanted messages, thus reducing the reliability and usefulness of electronic mail to the recipient. Some commercial electronic mail contains material that many recipients may consider vulgar or pornographic in nature.
The growth in unsolicited commercial electronic mail imposes significant monetary costs on providers of Internet access services, businesses, and educational and nonprofit institutions that carry and receive such mail, as there is a finite volume of mail that such providers, businesses, and institutions can handle without further investment in infrastructure. Many senders of unsolicited commercial electronic mail purposefully disguise the source of such mail.
Many senders of unsolicited commercial electronic mail purposefully include misleading information in the messages’ subject lines in order to induce the recipients to view the messages. While some senders of commercial electronic mail messages provide simple and reliable ways for recipients to reject (or ’opt-out’ of) receipt of commercial electronic mail from such senders in the future, other senders provide no such ’opt-out’ mechanism, or refuse to honor the requests of recipients not to receive electronic mail from such senders in the future, or both.
Many senders of bulk unsolicited commercial electronic mail use computer programs to gather large numbers of electronic mail addresses on an automated basis from Internet websites or online services where users must post their addresses in order to make full use of the website or service.
The problems associated with the rapid growth and abuse of unsolicited commercial electronic mail cannot be solved by the government alone. The development and adoption of technological approaches and the pursuit of cooperative efforts with other countries will be necessary as well.

Unwanted e-mail may ______.

A.cause companies to fail in business

B.cause wanted e-mail messages to lose

C.damage the credit of a company

D.do good to a small company