Fluorine atom. Diagram of an atom of the element fluorine, pulling back from the central nucleus to reveal the surrounding electron orbitals. - Vídeo de acervo HD

Fluorine is the ninth element, and has nine protons (red) in its nucleus, along with ten neutrons (blue). Fluorine has nine electrons, and each of its orbitals can hold a maximum of two. Orbitals are filled from the lowest energy (nearest the nucleus) first, so there are two electrons in the inner 1s orbital, and two in the higher energy 2s orbital (green spheres), two each in two of the slightly higher energy 2p orbitals (blue and yellow), and one in the last 2p orbital (red). For clarity, solid lines show the paths of the electrons. In reality, electrons can be found anywhere, and the shape of each orbital is based only on where it is most likely to be found