Chapter Seven: Ionic Bonds and Ionic Compounds

Formation of Ionic Compounds Compounds composed of cations and anions are called ionic compounds They are electrically neutral The total number of positive charges equals the same number of negative charges Because cations are positive and anions are negative, they are attracted to one another This is referred to as electrostatic forces Electrostatic forces create ionic bonds between cations and anions

How Does an Ionic Compound Form? The formation of positive and negative ions is simultaneous They are independent processes An ionic compound is the result of the transfer of electrons from one set of atoms to another set of atoms An ionic compound consists entirely of ions

Formula Units Chemical formulas represent the composition of substances It shows the number and kind of atoms present in the smallest representative unit of a substance Formula units are the way in which we represent ionic compounds Ex. NaCl, K 2 O, MgS Does the shape of the ionic crystal (Figure 7.8, p. 195) make sense based on what you know about opposing charges?

Properties of Ionic Compounds Most ionic compounds are crystalline structures at room temperature They form repeating three dimensional patterns The opposing charges are strongly attracted to one another and repulsions are minimized The large attractive forces form a very stable structure As a result, the melting point of ionic compounds is typically very high When dissolved in water, ionic compounds can conduct electric current – does this make sense?