ChemistryCode 9701
Electrons, energy levels and atomic orbitals
What this topic asks you to be able to do
- understand what is meant by shells, sub-shells and orbitals, the principal quantum number (n) and the ground state, with the scope limited to electronic configuration
- describe how many orbitals there are in s, p and d sub-shells, and how many electrons s, p and d sub-shells can each hold
- outline the sequence, from lowest to highest energy, of the sub-shells in the first three shells along with the 4s and 4p sub-shells
- outline electronic configurations so that they show how many electrons sit in every shell, sub-shell and orbital
- account for electronic configurations by reference to electron energy and inter-electron repulsion
- work out the electronic configuration of an atom or ion from its atomic or proton number and its charge, writing it in either the full form, e.g. for Fe: 1s2 2s2 2p6 3s2 3p6 3d6 4s2, or the shorthand form, [Ar] 3d6 4s2
- understand and apply the notation known as electrons in boxes, e.g. for Fe: [Ar]
- describe the shape of an s orbital and of a p orbital, and sketch both
- describe a free radical: any species that has at least one unpaired electron