Chemistry is all about predicting how different elements and compounds behave and react together. The rule of thumb is that:

• a metal reacts with a nonmetal to form a salt with ionic bonds Ionic bonding​
• a nonmetal reacts with another nonmetal to form a molecular compound with covalent bonds Covalent bonding​
• metals behave in a different fashion, with an exception of the amalgams of mercury in dental filling Metallic bonding​

In addition, advanced reactions include:

• acid-base neutralisation, which is why baking soda alleviates heartburn Acid-base reactions​
• galvanic corrosion, which is why boats rust in seawater Galvanic corrosion​