Shell Model for Molecules

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The diagrams above illustrate the Lewis picture of chemical covalent bonds as shared pairs of electrons. On the left, we have a hydrogen molecule, in which two hydrogen atoms share the single electron in their first shell, thus attaining the magic number two for a stable, filled first shell. On the right, lithium atoms, each with a single electron outside an inner already filled shell, can also form a single pair bond. As in the shell diagrams for single atoms, these molecular diagrams are useful for illustrating how certain molecules form. However, they are not, by any means, schematic diagrams of what molecules actually look like. (Unit: 6)