阅读理解
     John is a paper boy. He delivers（投递）newspapers to different houses in his street every day. He has about 80 customers（客户）. Half of his customers only take the newspapers on weekdays, and about half take the newspapers on weekdays and on Sundays. Two of John’s customers only take the newspapers on Sundays.
   John has to get up at 4：30 every morning to deliver his newspapers. It takes longer to deliver the newspapers on Sundays. The Sunday newspapers are twice as heavy as those on weekdays.
   John is saving his money to buy a new bicycle. He is also saving money for college （大学）. He has already saved 500 dollars

如图所示是张源同学在学校运动会上所拍摄的照片，她运用学过的物理知识对照片中的场景进行分析，下列分析正确的是（  ）

现对卤素单质Cl₂，Br₂，I₂的氧化性强弱进行探究，从而总结出在元素周期表中，同一主族元素非金属性变化规律．完成下列表格并得出结论

结论：（1）卤素单质Cl₂，Br₂，I₂的氧化性由强到弱的顺序____ 

（2）同一主族元素从上到下非金属性____ ．