问题 选择题

A、B、C、D、E是短周期五种元素,其原子序数逐渐增大。其中A与C是同族元素,B、E两元素间可形成酸雨,B、D简单离子具有相同的核外电子排布结构。下列说法正确的是(   )

A.氢化物的沸点:B<E           

B.简单离子半径:B>D

C.元素A与元素B不能形成化合物A2B2,但元素B与C能形成化合物C2B2 

D.元素D最高价氧化物一定能溶于强碱溶液

答案

答案:B

A、B、C、D、E原子序数逐渐增大,B、E两元素间可形成酸雨,所以B为O。E为S。B(氧离子)、D简单离子具有相同的核外电子排布结构,所以D为第三周期的金属元素镁或者铝。A与C是同族元素,C的原子序数比氧大,所以C为第三周期元素Na,A为H。A项,水分子间存在氢键,故沸点大于硫化氢。A错误。B项,核外电子排布相同的离子,原子序数越大,离子半径越小,所以B正确。C项,元素A与元素B能形成化合物HO,故C错误。D.元素D最高价氧化物可能是氢氧化镁,也可能是氢氧化铝,只有氢氧化铝能溶于强碱溶液,故D错误。选B

改错题

短文改错

       假定英语课上老师要求同桌之间交换修改作文, 请你修改你同桌写的以下作文。文中共有10处语言错误, 每句中最多有两处。每处错误仅涉及一个单词的增加、删除或修改。

     增加:在缺词处加一个漏字符号并在其下面写出该加的词。

     删除:把多余的词用斜线(\)划掉。

     修改:在错的词下划一横线, 并在该词下面写出修改后的词。

     注意:1.每处错误及其修改均仅限一词。

                 2. 只允许修改10处, 多者(从第11处起)不计分。

Dear Linda,

     We have some excited news for you. Maria is going to have a baby! We don't tell you right away.

At first the doctor said she might have some trouble of the baby. Now he says she is just fine. She still

works on his paintings every day. But she stopped from teaching her art classes.  There is going to have

another big change in our life. We're moving back to New York! It's very much nicer to be near the

families for something important like a baby. Maria grew up in Mexico, but she doesn’t have a family

here. So that makes even more important to us.

                                                                                                                Yours,

                                                                                                                 Dick

                                                                                                                                                             

单项选择题