化学 - 2026 进行中

科目: 化学
级别: I (I级最简单，XII级最难)
类别: 大学生
试题语言: English
题数: 15
问题示例: What does the atomic number of an element represent? The number of protons in its nucleus, The total number of neutrons and electrons, The number of electron shells, The mass of one atom in grams