Oxygen is a  very reactive gas. It makes up approximately 20%  of our atmosphere.   ​The standard test for oxygen is to place a glowing splint into a test tube that may contain the gas. If the splint glows brighter and/or relights into flame then it is a positive result for oxygen.

Introduction ​Hydrogen is a flammable gas. It burns in air to produce water. A convenient test for hydrogen is to put a lighted splint in the mouth of a test tube full of the gas . The gas will burn with a characteristic squeaky pop if hydrogen is present. Hydrogen gas can be used as a fuel.  When hydrogen burns in air it combines with ox...

Transition metals form coloured compounds

OCREdexcelAQA Transition elements : properties  Ligands and complex ions Ligand substitution and precipitation Redox reactions  Electron configurations  The video here  uses the relevant section of the Royal Society of Chemistry's periodic table website to show the electron configurations of the first row of the transition ...