It is found in the outermost electron shell of atoms. They can be identified by using a Lewis structure. An unfair bond: one is tighter while the other is rather loose. The electronegativities of the elements concerned are equal, as well as the sharing of electrons. The tendency of an atom/element to attract an electron, resulting in a negative charge, hence the name. Is the three-dimensional arrangement of the atoms that constitute a molecule. Refers to the overall charge of a molecule. A group of elements bonded together. Refers to an atom or a molecule with an excess proton. Refers to an atom or a molecule with an excess, unpaired electron. The basic unit of a chemical element.