Industrial Preparation: the Contact Process The Contact process makes sulphuric acid in four stages: Forming sulphur dioxide — by burning […]

The Electronic Theory of Bonding Atoms combine in fixed ratios to form new substances, mainly through interactions between their valence […]

Sulphur Sulphur sits in Group VI, period 3, making up about 0.1% of the Earth’s crust, and occurs as free […]

What’s Inside an Atom An atom is the smallest particle of an element that can take part in a chemical […]

Where Oxygen Comes From Oxygen sits in Group VI, period 2. It makes up 21% of atmospheric air by volume […]

Carbon Carbon is a Group IV, period 2 element — chemical symbol C, atomic number 6, electronic configuration 2,4. Allotropes […]

Group VII: An Overview The halogens — fluorine, chlorine, bromine and iodine — make up Group VII, each with seven […]

The pH Scale Acidity and basicity are measured on the pH scale, running from 0 to 14. Substances closer to […]

Phosphorus: An Overview Phosphorus is in Group V, period 3, with atomic number 15. It exists in several allotropic forms, […]

The First World War lasted from 1914 to 1918 and involved the major European powers and their colonies. Major Causes […]