How does bonding in oxides change across a period of the periodic table?

Across a period of the periodic table, the bonding in oxides exhibits a smooth transition from ionic to covalent as one moves from the metals on the left to the nonmetals on the right.1

This progression is accompanied by a corresponding shift in the acid-base character of the oxides, which transitions from strongly basic to strongly acidic. The general trend is as follows:2

• Ionic Bonding: Typically found in oxides of metals on the left side of the table (e.g., alkali metals and alkaline earth metals). These compounds contain the oxide anion ($O^{2-}$) and generally exhibit basic properties, reacting with water to form hydroxides.21
• Covalent Bonding: Found in oxides of nonmetals on the right side of the table. These are typically molecular in character and react with water to form acidic solutions.1
• Intermediate Character: As the bonding shifts toward covalent, the oxides may exhibit amphoteric behavior, meaning they can react as either an acid or a base.2

For example, in the third period, bonding progresses from ionic in $N{a}_{2}O$ and $MgO$ to covalent in $Si{O}_2$, $P_4{O}_{10}$, $S{O}_3$, and $C{l}_2{O}_7$.1