问题 选择题

下列说法中正确的是(   )

A.第3周期所含元素中钠的第一电离能最小

B.铝的第一电离能比镁的第一电离能大

C.在所有的元素中,F的第一电离能最大

D.钾的第一电离能比镁的第一电离能大

答案

答案:A

题目分析:金属性越强,第一电离能越小,同周期自左向右,金属性逐渐降低,所以选项A正确。由于镁元素的3s轨道电子是全充满状态,稳定性强,所以铝的第一电离能比镁的第一电离能小,B不正确。C不正确,应该是稀有气体的。同样根据元素周期律可知钾的第一电离能比镁的第一电离能小,答案选A。

点评:该题是基础性试题的考查,试题注重基础,主要是考查学生对第一电离能的变化规律的了解掌握情况,特别是规律中的一些反常的元素,有助于培养学生的逻辑思维能力和灵活应变能力,提高学生分析问题、解决问题的能力。

单项选择题
阅读理解

阅读理解。

     Many of like cooking but never have much time for it. Helen Fry's new book Quick Cooking has been

specially written for busy people. It has over 1,000 recipes, from the famous Spanish gazpacho to Swedish

smorgasbord. The book is well written and the photographs and drawings are clear. (They are like those in

the excellent little Quick Dressmaking and Quick Gardening.) The book has a strong plastic cover. It is easy

to find your way around it too. And busy people, notice this, Mrs. Fry tells you how much time you need in

order to get each dish ready.

     Quick Cooking has four parts, one for each season. This helps you to use fresh fruit and vegetable when

they are cheaper-and, of course, better. There are a lot of exciting ideas from foreign countries, and most of

the recipes are easy to follow. You take something simple like a chicken or some cheese, and make an unusual

dish out of it. For example, there are no fewer than 40 recipes for eggs! Mrs. Fry does not plan complete

meals for the "quick book". The beginners will have to find out a lot of things for himself or herself. But this

ought to be difficult with such a good book. I wanted to try many of the recipes as soon as I read them. For

people with little spare time, Helen Fry's Quick Cooking is excellent value.

1. Helen Fry's book is called Quick Cooking because _____. [ ]

A. You can cook all the dishes in it quickly

B. There is over 1,000 recipes in it

C. It is written for people who don't have much time

D. It tells you how to cook all kinds of food quickly

2. Busy people should notice that _____. [ ]

A. all the recipes in the book are easy to follow

B. there are clear photographs and drawings in the book

C. the book has a strange cover

D. they are told how long each dish takes to cook

3. This passage is most probably _____. [ ]

A. a book review

B. a notice

C. a letter to an editor

D. an introduction on cooking

4. We can infer from the passage that _____. [ ]

A. Helen Fry is good at writing books quickly

B. Complete meals are planned only for beginners

C. There are quite a few "quick books" for busy people

D. Beginners are advised to start making meals out of the cheapest materials