What Are Dot and Cross Diagrams - Part 1| Properties of Matter

Learn the basics about how to use dot and cross diagrams to represent covalent bonds. Dot and cross diagrams are simply a straightforward way of drawing the electrons in the orbitals of atoms and compounds. Most of the time, we use dots to represent electrons in orbitals. The electrons in the outer shell, the outer electrons, are known as valence electrons. These are the electrons that react. Atoms can bond as long as there is space in their outer shell to fit in more electrons. Dot and cross diagrams provide a useful way to keep track of where electrons come from, as the electrons from the original atoms are represented using dots and then you can represent foreign electrons with crosses. Or in reverse: the original atom electrons with crosses and the foreign electron with dots. Covalent bonding occurs when an atom doesn’t have the electrostatic force to steal another atom’s electrons like happens with ionic bonds. Instead, they share electrons. Dots and crosses are used to distinguish between neighbours in a bond, not between different elements. So the electrons of one oxygen may be represented with dots, and another oxygen's electrons with crosses.