Chemists use symbols and formulae to represent elements and compounds. Word equations and balanced chemical equations represent the changes that happen in chemical reactions. Mixtures - AQA There are ...

Players read questions about energy levels and score points by picking the correct element as the answer. Electrons are in regions around the nucleus that are different distances away from the nucleus ...

The covalent radius (a measure of how large individual atoms are) shows different trends if you are moving across a period or down a group. A comparison of the relative covalent radii of atoms is ...

The news broke that a railroad car, loaded with pure sodium, had just derailed and was spilling its contents. A television reporter called me for an explanation of why firefighters were not allowed to ...