问题 填空题

前四周期原子序数依次增大的元素A,B,C,D中,A和B的价电子层中未成对电子均只有1个,且A-和B+的电子相差为8;与B位于同一周期的C和D,它们价电子层中的未成对电子数分别为4和2,且原子序数相差为2。回答下列问题:

(1)D2+的价层电子排布图为_______。

(2)四种元素中第一电离最小的是________,电负性最大的是________。(填元素符号)

(3)A、B和D三种元素责成的一个化合物的晶胞如图所示。

①该化合物的化学式为_________;D的配位数为_______;

②列式计算该晶体的密度_______g·cm-3

(4)A-、B+和C3+三种离子组成的化合物B3CA6,其中化学键的类型有_____;该化合物中存在一个复杂离子,该离子的化学式为_______,配位体是____。

答案

(1)

(2)K;F

(3)①K2NiF4;6;②3.4

(4)离子键和配位键;[FeF6]3-;F-

前四周期原子序数依次增大的元素A、B、C、D中,A和B的价电子层中未成对电子均只有一个,并且A-和B+的电子数相差为8,A属于第VIIA族元素,B属于第IA族元素,且A的原子序数小于B,则A是F元素,B是K元素;与B位于同一周期的C和D,它们价电子层中的未成对电子数分别为4和2,且原子序数相差为2,且C和D的原子序数大于B,C的原子序数小于D,则C是Fe元素,D是Ni元素

(1)D2+的价层电子为3d电子,根据能量最低原理、保里不相容原理及洪特规则知,其价电子排布图为;

(2)元素的金属性越强其第一电离能越小,元素的非金属性越强,其电负性越大,这四种元素中金属性最强的是K元素,非金属性最强的元素是F,所以第一电离能最小的是K,电负性最大的是F;

(3)①该晶胞中A原子个数=16×1/4+4×1/2+2=8,B原子个数=8×1/4+2=4,D原子的个数=8×1/8+1=2,故该化合物的化学式为K2NiF4;由晶体的结构,D的配位数是6;

②该晶胞的体积=(400×10-10cm)2(1308×10-10cm)

(4)A-、B+和C3+三种离子组成的化合物的K3FeF6,该物质中阴阳离子间存在离子键,铁原子和氟原子间存在配位键,该化合物中存在一个复杂离子,该离子的化学式为[FeF6]3-,配位体是F-

阅读理解

阅读理解。

     Do you love holidays but hate the increase weight that follows? You are not alone.

     Holidays are happy days with pleasure and delicious foods. Many people, however, are worried

about the weight that comes along with the delicious foods. With proper planning, though, it is possible

to control your weight. The idea is to enjoy the holidays but not to eat too much. You don't have to

turn away from the foods that you enjoy. The following suggestions may be of some help to you.

     Do not miss meals. Before you leave home for a feast, have a small, low-fat snack. This may

help to keep you from getting too excited before delicious foods.

     Begin with clear soup and fruit or vegetables. A large glass of water before you eat may help

you feel full .Use a small plate; a large plate will encourage you to have more than enough.

     Better not have high-fat foods. Dishes that look oily or creamy have much fat in them.

     Choose lean meat. Fill your plate with salad and green vegetables. If you have a sweet tooth ,

try mints (薄荷) and fruits .They don't have fat content as cream and chocolate.

     Don't let exercise take a break during the holidays. A 20-minute walk after a meal can help

burn off excess calories.

1. In order to really enjoy your holidays without putting on weight, you'd better__________.

A. drink much water and have vegetables only      

B. not eat much food in high-fat

C. not accept invitations to feasts                  

D. turn away from delicious foods

2. Many people can't help putting on weight after the holidays because they __________

A. go to too many feasts        

B. can't help turning away from the foods                      

C. enjoy delicious foods        

D. can't control themselves

3. Excess calories can be found in your body in the form of _________

A. energy    

B. fat        

C. food        

D. something invisible

单项选择题