X、Y、Z是原子序数依次增大的短周期元素,3种元素的原子核外电子数之和与Ca2+

题型:选择题

问题:

X、Y、Z是原子序数依次增大的短周期元素,3种元素的原子核外电子数之和与Ca2的核外电子数相等,X、Z分别得到一个电子后均形成稀有气体原子的稳定电子层结构。下列说法正确的是(  )

A.原子半径:Z>Y>X

B.Z和X形成化合物的稳定性大于Z的同族元素与X形成化合物的稳定性

C.Na2Y2与水发生反应时,Na2Y2只作氧化剂

D.在CaX2、CaY2和CaZ2三种化合物中,阳离子与阴离子的个数比均为1∶2

考点:构成物质的粒子—分子、原子、离子元素周期律
题型:选择题

某一摄影师去丛林地区采风,当地正流行氯喹抗性疟疾,为预防她提前服用了药物但不幸仍然感染了急性疟疾。

预防性服用的药物为()

A.氯喹

B.甲氟喹

C.青蒿素

D.伯氨喹

E.奎宁

题型:选择题

短文改错。

    I often quarrel about my mother over whether I can watch TV after school. She holds view that senior one

students have to make fully use of every minute to work hard at their lessons. It seems to me that once I am

allowed to do that. I will unable to control myself and forget all about my study. She also thinks it is bad for

my eye. But I really can not accept her ideas. In my opinion, watch TV can set my mind at rest after a day's

a hard works. Besides, it is important for us to know what had happened at home and at abroad. Thus, we

shouldn't be forbidden to watch TV.

________________________________________________________________________________________

题型:选择题

在世界史上,()是最早创立较系统的军事理论的国家。

A、美国

B、德国

C、中国

D、英国

题型:选择题

简述接触胶结和溶蚀胶结的基本特点。

题型:选择题

板式塔流体流动性能的测定:在板式塔实验中,试说明从溢流点到泄漏点气速和压降的关系?

更多题库