A sodium atom transfers an electron to a chlorine atom to create table salt.

An IONIC BOND is an electrostatic interaction that holds together a positively charged ion (cation) and a negatively charged ion (anion). In an ionic bond, one atom loses an electron to another atom, forming a cation and anion, respectively. And, as everyone knows, opposites attract.

A neutral atom becomes an ion either by losing an electron (cation) or by gaining an electron (anion).

In table salt, for example, a valence electron from a sodium atom is transferred to a chlorine atom, forming Na+ and Cl-. Because the ions have opposite charges, they are attracted to each other. The loss of a valence electron and the attraction to the atom that took it happen simultaneously.

It is possible for more than one valence electron to be drawn away from another atom, as in barium chloride (BaCl₂, a substance used in medicinal preparations). In barium chloride, two chlorine atoms each take one valence electron away from barium, leaving the barium ion Ba²⁺.

Unlike water or oxygen, which have covalent bonds, substances that have ionic bonds do not exist naturally as discrete molecules. Rather, they form IONIC SOLIDS, three-dimensional networks in which each cation is surrounded by anions and each anion is surrounded by cations.

Sodium chloride results from ionic bonding.

Look again in the saltshaker. Each sodium cation is surrounded or ionically bonded to six chloride anions, and each chloride anion is ionically bonded to six sodium cations. The formula NaCl for sodium chloride shows that for every sodium atom present in a piece of salt, there is one chlorine atom present. What, don't see any ionic bonds? All right, it looks like this:

Where are ionic bonds found? These types of bonds usually form when metal atoms bond with nonmetal atoms. In salt, the metal sodium bonds with the nonmetal chlorine. Besides salt, some other examples are lithium fluoride (LiF), strontium oxide (SrO) and calcium chloride (CaCl₂).

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