The Continuum of Bonding Across a Period

A metal and a nonmetal—elements from opposite sides of the periodic table— have a relatively large AEN and typically interact by electron transfer to form an ionic compound. Two nonmetals—elements from the same side of the table— have a small AEN and interact by electron sharing to form a covalent compound. When we combine the nonmetal chlorine with each of the other elements in Period 3, starting with sodium, we should observe a steady decrease in AEN and a gradation in bond type from ionic through polar covalent to nonpolar covalent. 

The tendency toward less ionic and more covalent character in the bonds continues through SiCU, PCI3, and SCC. Each of these compounds occurs as separate 

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