Chemistry

Noble gases are He, Ne, Ar, Kr, Xe, Rn. Helium has a filled shell of 2 electrons. All the rest have 8 electrons in their…

Changes in electron distribution are best described using Oxidation Numbers. Oxidation Number (O.N.) is a way of describing how the electron density around an atom…

Covalent bonding occurs when too many electrons (typically 3 or more) have to be transferred for ionic bonding to be energetically favourable. Outer octet achieved…

Drawing atoms and ions with all the orbits or orbitals is time consuming. We usually draw Lewis diagrams to represent the way that electrons form…

Bohr’s theory was a start but it only explained the hydrogen atom (one electron as a particle orbiting around a nucleus). The Quantum-Mechanical (QM) model,…

The simplest spectra to study are those of H, as it only has one electron. These contain sets of lines which can be related to…

Moving an electron between a lower and higher energy level can only be achieved if it absorbs energy of a particular amount; this could be…

Emission and absorption spectra are evidence that the electrons within an atom have quantised energies i.e. an electron cannot possess a continuous range of values…

An element can also absorb light at specific wavelengths. An absorption spectrum can be obtained by passing a continuous radiation spectrum (white light) through a…

Often, in analytical work, it is necessary to know how to prepare a more dilute solution from a more concentrated one. This process is called…