Arrangement of Electrons in Atoms

Electron Arrangement

• Each shell is numbered 1, 2, 3, and so on, going outwards from the nucleus.
• The arrangement of electrons in the atom can be written as the electronic configuration or arrangement shown below:

• The electronic structure of an atom can be shown and drawn as a “dot and cross” diagram.
• The shell furthest from the nucleus is called the outermost shell or valence shell.

Valence Electrons

• they are involved in the chemical bonding between atoms.
• they are important in chemical reactions
• they determine the chemical properties of the element
• The further the distance from the nucleus, the weaker the attraction of the electrons.