题目

The Pacific island nation of Nauru used to be a beautiful place. Now it is an ecological disaster area. Nauru’s heartbreaking story could have one good consequence — other countries might learn from its mistakes. For thousands of years, Polynesian people lived on the remote island of Nauru, far from western civilization. The first European to arrive was John Fearn in 1798. He was the British captain of the Hunter, a whaling ship. He called the island Pleasant Island. However, because it was very remote, Nauru had little communication with Europeans at first. The whaling ships and oth2．短周期主族元素A、B、C、D、E原子序数依次增大，C在短周期主族元素中原子半径最大；A与C，B与D 分别位于同一主族，且B与D原子序数之和恰好是 A与C原子序数之和的2倍．请回答下列问题：（1）D元素在元素周期表中的位置第三周期ⅥA族．（2）C2B2的电子式为．（3）B、C、D、E所形成简单离子的半径由大到小的顺序是S2-＞Cl-＞O2-＞Na+（填离子符号）．（4）实验室欲检验CE溶液中所含的E-，操作方法和现象为取少量溶液于试管中，先加稀硝酸酸化再加硝酸银，若有白色沉淀产生，则证明有氯离子．（5）Cu不与稀硫酸反应，但将Cu投入稀硫酸与A2B2的混合溶液，溶液变蓝，写出其离子反应方程式Cu+2H++H2O2=Cu2++2H2O．