


They have been produced in a laboratory and are not naturally occurring, often having a very brief existence. Bear in mind, however, that element numbers 95 to 118 in the periodic table are all synthetic radioisotopes. When dealing with the complexity of an atom's electron configuration, therefore, the worst-case scenario is that we have one hundred and eighteen electrons to consider.

The last element in the table is oganesson ( Og), which has the atomic number one hundred and eighteen ( 118) because it has one hundred and eighteen protons and one hundred and eighteen electrons. The first element in the table is hydrogen ( H), which has the atomic number one ( 1) because it has one proton and one electron. At the time of writing, the periodic table contains one hundred and eighteen ( 118) elements. For that reason, we will start by by exploring the concept of electron shells, and then go on to examine the concept of orbitals.īefore we do anything else, let's try and get a little perspective. Nevertheless, the Rutherford-Bohr model is still taught in schools and colleges because it gives us a good conceptual framework for thinking about electrons and their energy levels. They certainly do not occupy neat circular orbits - the reality is far more complex.

We know now that the Rutherford-Bohr model does not accurately represent the way in which electrons behave. Whereas the planetary orbits in our solar system all lie on (or very close to) a two-dimensional orbital plane, electron orbits were believed to occupy a number of different orbital planes, spawning the concept of three-dimensional electron shells. Electrons with higher energy levels would occupy higher orbits. The electrons with the lowest energy levels occupied the lowest orbits. According to the Rutherford-Bohr model, electrons were thought to occupy fixed, circular orbits around the nucleus of an atom.
