问题 填空题

氮元素可以形成多种化合物。回答以下问题:

(1)基态氮原子的价电子排布式是                          

(2)C、N、O三种元素第一电离能从大到小的顺序是                     

(3)肼(N2H4)分子可视为NH3分子中的一个氢原子被—NH2(氨基)取代形成的另一种氮的氢化物。

①NH3分子的空间构型是          ;N2H4分子中氮原子轨道的杂化类型是________。

②肼可用作火箭燃料,燃烧时发生的反应是:

N2O4(l)+2N2H4(l)===3N2(g)+4H2O(g) ΔH=-1 038.7 kJ·mol-1

若该反应中有4 mol N—H键断裂,则形成的π键有________mol。

答案

(1)1s22s22p3 (2)N>O>C  (3)①三角锥形;sp3    ②3

题目分析:(1)根据构造原理可知,基态氮原子的价电子排布式是1s22s22p3

(2)非金属性越强,第一电离能越大。但由于氮元素的2p轨道电子处于半充满状态,所以第一电离能大于氧元素的,则C、N、O三种元素第一电离能从大到小的顺序是N>O>C。

(3)①氨气分子中氮原子含有的孤对电子对数=(5-3×1)÷2=1,所以氨气是三角锥形结构。肼(N2H4)分子可视为NH3分子中的一个氢原子被-NH2(氨基)取代形成的另一种氮的氢化物,所以氮原子仍然是sp3杂化。

②根据热化学方程式可知,若该反应中有4 mol N—H键断裂,则生成氮气的物质的量是1.5mol。由于氮气含有三键,而三键是有1个α键和2个π键形成,所以形成的π键有1.5mol×2=3mol。

点评:该题是高考中的常见题型,属于中等难度的试题。试题基础性强,侧重对学生能力的培养和解题方法的指导与训练,旨在考查学生灵活运用基础知识解决实际问题的能力,有利于培养学生的应试能力和逻辑推理能力。该题以“周期表中元素的推断”为载体,比较全面考查学生有关元素推断知识和灵活运用知识的能力。考查学生对元素周期表的熟悉程度及其对表中各元素性质和相应原子结构的周期性递变规律的认识和掌握程度。考查了学生对物质结构与性质关系以及运用元素周期律解决具体化学问题的能力。

阅读理解

任务型阅读:  下面的五个人都想找房子,以下各题是他们的个人情况介绍.阅读所给出的六则广告简介(A---F).选出符合个人需要的最佳选项.选项中有一项是多余的.

__小题1:Mr. and Mrs. Robinson have four children. They haven't got a car, so they want to live downtown. They can pay $500 a month, but they can't pay more than that.

小题2:Mr. Smith has been retired and he is alone. He is now not in good health. He wants a house in the country which is very quiet and near to see the doctor.

__小题3:The Williams are very rich, and they want to find a clean and comfortable house. They have a lot of friends and often invite them to spend the weekend in their house.

__小题4: Mrs. White has a young daughter who is only seven years old, but she doesn't want to spend too much time sending her child to school. And she also likes a house near a park or the forest.

__小题5: Mr. Jackson is a truck driver and he has two children, one of whom has a car and is going to get married. So they want to find a house where they can park their car and truck easily.

A:  A small house in the country, two miles from a village but near a hospital,  450 dollars a month. Call 821-7146 for an evening or Sunday appointment.

B:  Now available at Franklin Park, one block from a primary school. Two bedrooms at $225. Utilities included except electricity. One month's deposit(押金)required.

C:  A flat of 120 square meters, with three bedrooms, a bathroom and a kitchen is in a building on New Street, which is not far from the center of the city. In each bedroom there is a bed, a sofa, a desk and two chairs. The rent is $480 per month. Five or six buses take you straight to the school, the hospital, the supermarket, and the train station.

D:  Nice modern apartment with nine bedrooms, a swimming pool and lovely gardens, start Jan. 1, partly furnished, with water and dryer, central air conditioning, 1800 dollars a month.

E:  A house available for rent-furnished. Street Croix, Virgin, pool, wide ocean view. No buses but a parking lot nearby, $200 weekly. November--April. SR Box Y---680.

单项选择题