题目

现有8种元素的性质、数据如下表所列，它们属于第二或第三周期。 回答下列问题：      ①②③④⑤⑥⑦⑧ 原子半径(10－10m)0.741.601.521.100.991.860.750.82 最高或最低化合价 ＋2＋1＋5＋7＋1＋5＋3 －2 －3－1 －3（1）③的元素符号是               ，⑧的元素名称是               。 ①在元素周期表中的位置是（周期、族）             。 （2）在最高价氧化物的水化物中，酸性最强的化合物的分子式是              ； 名短文改错 　　Antarctica(南极洲) is one of the seven continents(洲) in the world. It is a continent with mountains 1．________ and ice. It is a cold and alone place. The South 2．________ Pole is 1000 kilometres to the coast, Winds of 3．________ 150 kilometres an hour blows over it. On the 4．________ coast is a big wall of ice. Icebergs break off into the sea. Penguins(企鹅) live in near the water. 5．________ They catch fish their food. No land animals 6．________ live there. Flowers and trees do not grow there. People go to Antarctica by ships and in planes. They 7．________ learn the weather and the penguins there. in 8．________ spring, they leave their camp and travel cross 9．________ the snow in tractors. They study the rocks in the snow and make maps of the new places. 10．________