HKDSE chemistry 5**化學影片 Topic 5 Radioactivity and Nuclear Energy 17. Radiation and radioactivity 18. Atomic model 19. Nuclear energy 唔明?點撃預約$99試堂! 想下載dse試卷?Click here! 想睇埋Biology影片?Click here! 想睇埋Physics影片?Click here! 化學補習 生物補習 物理補習 化學練習 生物練習 物理練習