Particles > Structure and properties of matter > Types of bonds
Electromagnetic forces are responsible for non-temporary attractions between atoms that lead to the formation of chemical bonds and the creation of molecules. There are two main types of bonds, covalent and ionic. The ionic bond is due to the electrostatic force of attraction between atoms with opposite charges while the covalent one occurs through the sharing of one or more electrons.
Connection to Big Idea about energy: Chemical compounds are formed by the joining of two or more atoms either from the same or from different elements. A stable compound occurs when the total energy of the combination has lower energy than the separated atoms. The bound state implies a net attractive force between the atoms resulting to a chemical bond.
Connection to Big Idea about forces: The electromagnetic force forms the bonds between atoms and determine the geometry of molecules. The charge distribution of the atoms involved defines the type of bonds between them and consequently the geometry of molecules.
Connection to Big Idea about quantum: All bonds can be explained by quantum theory, but, in practice, simplification rules allow scientists to predict the strength, directionality, and polarity of bonds.
Connection to Big Idea about the cell: Chemical bonds hold molecules together and create temporary connections that are essential to life. Both strong and weak bonds play key roles in the chemistry of our cells and bodies. For instance, strong covalent bonds hold together the chemical building blocks that make up a strand of DNA. On the other hand, weaker hydrogen bonds hold together the two strands of the DNA double helix. These weak bonds keep the DNA stable, but also allow it to be opened up for copying and use by the cell.
Subjects related: Chemistry
Age ranges: 13-14,14-15,15-16,16-17,17-18