Bonding

There are two types of bonding in atoms - ionic and covalent.

Ionic bonds are when two elements join and exchange electrons. They usually form when a metal and a nonmetal bind together. Ionic bonds are responsible for salt, a mixture of chlorine and sodium, or copper fluoride. Ionic bonds tend to form crystals. They have high melting points. They are hard and brittle, dissolving in water, and conduct electricity when dissolved. Ionic bonds prefer to have eight valence electrons, to satisfy the octet rule. The octet rule states that atoms want to have eight valence electrons. When they do, they are at their most stable. Ionic bonds are like Lego sculptures. If you hit them, your hand will just bounce off because they're tightly packed. Your hand might also hurt, too, depending on how hard you hit it.

Covalent compounds are different. They are usually formed when two nonmetals bind together. Covalent bonds are different because they share electrons, not exchange them. Covalent compounds are things like carbohydrates, proteins and water. They are strong but flexible. If you hit a covalent compound, it would be less like hitting a Lego sculpture, and more like hitting a ball pit. They have low melting points, compared to ionic compounds, and don't easily dissolve in water.