Chapter 15 The p-block elements (I) ק15.1 The halogens x*§15.2 The rare gases x 15.3 The property variations for compounds of p-block elementsChapter 15 The p-block elements (Ⅲ) §15.3 The property variations for compounds of p-block elements *§15.2 The rare gases §15.1 The halogens