题目

由如图1和如图2可知：（1）该元素属于_________________元素（2）该元素原子的相对原子质量________________（3）该原子结构示意图中m的值_____________ 答案：【答案】金属 47.87 10 【解析】（1）钛元素元素名称中含“钅”旁，属于金属元素；（2）根据元素周期表中一格信息，元素名称下方数字表示该元素原子的相对原子质量，故填47.84；（3）根据原子核内质子数＝核外电子数，22＝2+8+m+2，得m=10。It seems to be strange to you that there is a blind spot (盲点) on the eyes. Here is an interesting experiment (实验) that can make something disappear (消失), when one eye is open.Make a card about the size of a postcard and write two English letters L and R on it, L on the left and R on the right. First, hold the card about 80 cm away and you see both the letters. Then close your right eye and look at the letter R only with your left eye. And now, as you move the card slowly towards you, you’ll find the letter L disappearing. But if you move the card nearer to your face, you can see the letter again. Now do the same experiment with your left eye closed, you’ll find the letter R disappearing.Why does the letter disappear? It is because there is a blind spot on the eyes. When the image (影像) of the letter falls on the blind spot, you can’t see it. That is why either of the letters disappears.【1】The writer of the passage thinks that ______________there is a blind spot on the eyes.A. few people know B. no one knowsC. most people know D. all the people know【2】You fail to see the letter L in the experiment because ______________.A. your eyes are poor B. its image falls on the blind spotC. your left eye is not open D. you move it close to your eye【3】In which order (顺序) should you do the experiment?①Hold /span>the card②Move the card nearer③Close your right eye④Write two English letters⑤Look at the letter R ⑥Make a cardA. ④⑥①②③⑤ B. ①③⑥④⑤②C. ⑥①④③②⑤ D. ⑥④①③⑤②【4】The passage mainly (主要) tells us ______________.A. the blind spot can moveB. an interesting experimentC. where the blind spot isD. there is a blind spot on the eyes