Ionic Compounds Compounds can be broken into several categories. The first type of compound we are going to study are ionic compounds. Ionic compounds are made up of substances known as ions. Ions are atoms that have either lost or gained electrons causing them to have a positive charge (lost electrons) or a negative charge (gained electrons)

We already know that positive and negative charges attract. The attraction between a positive ion and a negative ion is called an ionic bond. Metals tend to lose electrons becoming positive ions while nonmetals tend to gain electrons becoming negative ions. Binary ionic compounds are ionic compounds that contain just two elements. Binary ionic compounds: (1) Are made up of positive and negative ions; and (2) Contain a metal (+ ion) and a nonmetal (- ion)

What happens when a sodium atom collides with a chlorine atom? Since chlorine has the greater attraction for electrons, it pulls the valence electron from sodium and fills its outer energy level, forming a stable octet. By gaining an electron, chlorine becomes an anion with a -1 charge called a chloride ion. By losing its valence electron, sodium is left with a stable octet and becomes a cation with a +1 charge called a sodium ion.

The oppositely charged ions of sodium and chloride attract each other very strongly. This attraction causes an ionic bond to form. The result of this ionic bond is the ionic compound called sodium chloride. Since the compound contains a single sodium ion and a single chloride ion, the chemical formula for sodium chloride is NaCl. Note: the net (overall) charge of an ionic compound is always zero. ie (-1) = 0

Show what happens when magnesium and chlorine atoms collide using Lewis diagrams. Write the formula of the compound that results and name it.