The number of protons in an atom determines what element it will be, so the number of protons is called the atomic number of that element. For most of the 16 lightest elements (up to oxygen) the numbe...The number of protons in an atom determines what element it will be, so the number of protons is called the atomic number of that element. For most of the 16 lightest elements (up to oxygen) the number of neutrons is equal to the number of protons. For elements that do not have a full outer shell (e.g., lithium, Figure 5.6 left), the outermost electrons can interact with the outermost electrons of nearby atoms to create chemical bonds.
