题目

     Imagine an eco-conscious city where rooftops have been transformed into fertile, green gardens． It's a place where every home is equipped with a system that recycles valuable water resources． In this town, protecting the planet is a way of life．That's how Abby Sharp, 14, Wyatt Peery, 13, and Tom Krajnak, 14, saw their city of tomorrow．The vision won the eighth-graders from Bexley, Ohio: first prize at the 2009 National Engineers Week Future City Competition．    The annual design competition challenges middle school students to use engineering to deal with issues that affec下图所示是镁和氯两种元素的相关信息．下列说法错误的是（ ）A．镁元素的原子序数为12B．镁元素是金属元素，氯元素是非金属元素C．镁元素与氯元素的最本质的区别是原子中质子数不同D．两种元素组成的化合物中镁原子与氯原子的数目比为1：1