Metacognition is  cognition about cognition, thinking about thinking, or knowing about knowing. It comes from the root word  meta , meaning beyond. It can take many forms; it includes knowledge about when and how to use particular strategies for learning or for problem solving. There are generally two components of metacognition: knowledge about cognition, and regulation of cognition.
In chemistry, an ionic compound is a chemical compound in which ions are held together in a structure by electrostatic forces termed ionic bonds.The positively charged ions are called cations and the negatively charged ions are called anions.onic compounds without the acidic hydrogen ion (H +), or the basic ions hydroxide (OH â) or oxide (O 2â), are also known as salts and can be formed by acid-base reactions. Ionic compounds containing hydrogen ions are classified as acids and compounds containing hydroxide or oxide ions are classified as bases.
The composition of ionic compounds is determined by the requirement that the compounds must be electrically neutral. That is that the charges of the cations and anions must balance or 'cancel out one another. For example consider sodium cations (Na+) and Chlorine anions (Cl-).