题目

X、Y、Z、Q、E五种元素中，X原子核外的M层中只有两对成对电子，Y原子核外的L层电子数是K层的两倍，Z是地壳内含量(质量分数)最高的元素，Q的核电荷数是X与Z的核电荷数之和，E在元素周期表的各元素中电负性最大。请回答下列问题： (1)X、Y的元素符号依次为________________________________________（2分） (2)XZ2与YZ2分子的立体结构分别是__________（2分）和______________（2分），相同条件下两者在水中的溶解度较大的是__________(写分子式) （2分），理由是_______________阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。In this constantly changing world, how to put the knowledge 【1】 (gain) every day into reality has interested numerous people. As a proverb goes, "Knowledge is a treasure, but practice is the key 【2】 it. " Apparently, this saying 【3】 (try) to deliver the message that we ought not to stop practicing it if we 【4】 (true) want to master the knowledge we learn.There are several reasons 【5】 (account) for this statement. To begin with, human beings are 【6】 (forget) beings; therefore, only 【7】 we use knowledge, make mistakes, and try to use it again will we be able to remember it by heart. 【8】 ,knowledge has become growingly complicated and we can seldom grasp the essence(实质)of it if we do not practice it again and again.Practicing over and over, to sum up, 【9】 (be) of the greatest importance for those who are determined to learn knowledge well. As a student, I hope that 【10】 young can focus more attention on practicing what they learn.