The chlorine atom borrows an electron from the sodium atom, becoming negatively charged in the process by the addition of this extra electron, while, vice versa, the sodium atom becomes positively charged. These charged atoms, now called “ions,” are attracted to each other because of their opposite charges, and they cling together to form the compound known as sodium chloride, or common salt.

From two seemingly unlikely building blocks with their own distinctive properties we get the common salt so vital for life. This rearrangement with regard to only one electron builds a completely new substance! A combination like this is called an electrovalent bond.

[Diagram on page 14]

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Combining of Sodium and Chlorine Atoms

Sodium Chlorine + −

Atoms (showing only Ions​—forming

outer electron shells) sodium chloride