This course is the third part of a comprehensive introduction to Chemistry, covering everything you will need to know as you prepare for possible future exams. It doesn't matter how much, or how little, prior knowledge of Chemistry you've got as this course will take you through all the necessary stages.The Principles of Chemistry, there are five video lessons, each one lasting about 20 minutes. The first lesson introduces the states of matter and atomic structure.  In the next lesson we progress to relative formula mass and chemical equations - don't be put off by these as everything is very carefully explained!  Lesson 3 covers chemical formulae, and we progress in lesson four to look at reacting masses, ionic bonding and covalent bonding.