How do chemists explain the properties of compounds of Group 1 and Group 7 elements?
OCR GCSE 21st Century Additional Science and GCSE Twenty First Century Chemistry Module Unit C4: Chemical Patterns Part of OCR GCSE 21st Century Additional Science A Unit 1 examination paper foundation (A215/01) and higher (A215/02) and for OCR 21st Century GCSE Chemistry A Unit 2 Modules C4, C5 and C6 examination paper foundation (A322/01) and higher (A322/02)