This page covers the following topics:
The electronic strucutre is the way in which electrons are arranged in an atom. Electrons in atom are arranged in shells (or energy levels) surrounding the nucleus. The electrons in an atom occupy the shell nearest the nucleus first, until it is full. The first shell can contain 2 electrons. The second and third can contain 8. The electronic structure can be written as a number (x, y, z); x represents the number of atoms in the first shell, y the second and z the third.
Dot and cross diagrams are a simple way of visualising electrons in the orbitals of atoms and compounds. The electrons in the outer shell are known as vlence electrons, which react. Atoms can bond if there is space in their outer shell to fit more electrons.
The diagram represents the shells that the electrons are in. For example, carbon has 2 electrons in the first shell, and four in second.
In an atom, electrons reside in energy levels known as shells. The energy increases as the shell increases. Shells are made up of atomic orbitals, which are regions around the nucleus that can hold up to two electrons, with opposite spins. There are s-, p- and d- orbitals, each with a different shape. Each shell contains one s-orbital, and from shell 3, each shell also contains 3 p-orbitals (sub-shells), and from shell 3, each shell also contains 5 d-orbitals. Shells fill up in order s --> p --> d. The electron configuration is now written as 1sa 2sb 2pc 3sd 3pe with the superscript letters representing the number of electrons in the orbital.
End of page