Oxides are two element compounds (with one being oxygen). They can be acidic, amphoteric or basic.
Acidic oxides react with hydroxide ions to form oxyanions (negatively charged ions) and water. If they are soluble, they react with water to form oxyacids (acids with the corresponding element), Hydrogen, and oxygen. They consist of molecules with hydroxyl groups, and they undergo partial ionisation with water to produce hydronium ions. They are the oxides of non metals.
Basic oxides react with acids or h+ to produce positively charged metal ions and water (the solid appears to dissolve). If soluble, they form metal ions and hydroxide ions. They are the oxides of metals.
Amphoteric oxides react with acids to produce positive monatomic ions and water, as well as reactinve with hydroxide ions to produce oxyanions and water. They are all insoluble.