Fluorine is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. As the most electronegative element, it is extremely reactive: almost all other elements, including some noble gases, form compounds with fluorine.
Owing to the expense of refining pure fluorine, most commercial applications use fluorine compounds, with about half of mined fluorite used in steelmaking.
Fluorine is obtained by the electrolysis of a solution of potassium hydrogendifluoride in anhydrous hydrofluoric acid.
Protons and Neutrons in Fluorine
Fluorine is a chemical element with atomic number 9 which means there are 9 protons in its nucleus. Total number of protons in the nucleus is called the atomic number of the atom and is given the symbol Z. The total electrical charge of the nucleus is therefore +Ze, where e (elementary charge) equals to 1,602 x 10-19 coulombs.
The total number of neutrons in the nucleus of an atom is called the neutron number of the atom and is given the symbol N. Neutron number plus atomic number equals atomic mass number: N+Z=A. The difference between the neutron number and the atomic number is known as the neutron excess: D = N – Z = A – 2Z.
For stable elements, there is usually a variety of stable isotopes. Isotopes are nuclides that have the same atomic number and are therefore the same element, but differ in the number of neutrons. Mass numbers of typical isotopes of Fluorine are 19.
Main Isotopes of Fluorine
Only one isotope of fluorine occurs naturally in abundance, the stable isotope 19F. The isotopes 17F and 18F undergo β+ decay and electron capture, lighter isotopes decay by proton emission, and those heavier than 19F undergo β− decay (the heaviest ones with delayed neutron emission).
Fluorine-19 is composed of 9 protons, 10 neutrons, and 9 electrons. Its abundance is 100%; no other isotopes of fluorine exist in significant quantities.
Fluorine-18 is composed of 9 protons, 9 neutrons, and 9 electrons. Of the unstable nuclides of fluorine, 18F has the longest half-life, 109.739 minutes. It has two decay modes, of which the main one is positron emission. For this reason 18F is a commercially important source of positrons.
Fluorine-20 is composed of 9 protons, 11 neutrons, and 9 electrons. Fluorine-20 is one of the more unstable isotopes of fluorine. It has a half-life of 11.07 seconds and undergoes beta decay.
Stable Isotopes
| Isotope | Abundance | Neutron Number |
| 19F | 100% | 10 |
Typical Unstable Isotopes
| Isotope | Half-life | Decay Mode | Product |
| 18F | 109.8 min | positron decay | 18O |
| 20F | 11.163(8) s | beta decay | 20Ne |
Electrons and Electron Configuration
The number of electrons in an electrically-neutral atom is the same as the number of protons in the nucleus. Therefore, the number of electrons in neutral atom of Fluorine is 9. Each electron is influenced by the electric fields produced by the positive nuclear charge and the other (Z – 1) negative electrons in the atom.
Since the number of electrons and their arrangement are responsible for the chemical behavior of atoms, the atomic number identifies the various chemical elements. The configuration of these electrons follows from the principles of quantum mechanics. The number of electrons in each element’s electron shells, particularly the outermost valence shell, is the primary factor in determining its chemical bonding behavior. In the periodic table, the elements are listed in order of increasing atomic number Z.
Electron configuration of Fluorine is [He] 2s2 2p5.
Possible oxidation states are -1.
Fluorine forms a great variety of chemical compounds, within which it always adopts an oxidation state of −1. With other atoms, fluorine forms either polar covalent bonds or ionic bonds. Most frequently, covalent bonds involving fluorine atoms are single bonds, although at least two examples of a higher order bond exist. Fluorine’s chemistry includes inorganic compounds formed with hydrogen, metals, nonmetals, and even noble gases; as well as a diverse set of organic compounds.
Typical Chemical Compound of Fluorine
Uranium conversion is one of processes of nuclear fuel cycles, in which uranium is chemically purified and converted into the chemical form of uranium hexafluoride (UF6), the input stock for most commercial uranium enrichment facilities. Uranium hexafluoride, known also as “hex”, is a chemical compound used in the process of enriching uranium, which produces fuel for nuclear reactors. At atmospheric pressure, uranium hexafluoride sublimes at 56.5 °C. At this stage of the cycle the uranium hexafluoride conversion product still has the natural isotopic mix, i.e. it contains only 0.71% of fissile isotope 235U.
A proton is one of the subatomic particles that make up matter. In the universe, protons are abundant, making up about half of all visible matter. It has a positive electric charge (+1e) and a rest mass equal to 1.67262 × 10−27 kg (938.272 MeV/c2)— marginally lighter than that of the neutron but nearly 1836 times greater than that of the electron. The proton has a mean square radius of about 0.87 × 10−15 m, or 0.87 fm, and it is a spin – ½ fermion.
The protons exist in the nuclei of typical atoms, along with their neutral counterparts, the neutrons. Neutrons and protons, commonly called nucleons, are bound together in the atomic nucleus, where they account for 99.9 percent of the atom’s mass. Research in high-energy particle physics in the 20th century revealed that neither the neutron nor the proton is not the smallest building block of matter.
The periodic table is a tabular display of the chemical elements organized on the basis of their atomic numbers, electron configurations, and chemical properties. The electron configuration is the distribution of electrons of an atom or molecule (or other physical structure) in atomic or molecular orbitals. Knowledge of the electron configuration of different atoms is useful in understanding the structure of the periodic table of elements.
Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms. The chemical properties of the atom are determined by the number of protons, in fact, by number and arrangement of electrons. The configuration of these electrons follows from the principles of quantum mechanics. The number of electrons in each element’s electron shells, particularly the outermost valence shell, is the primary factor in determining its chemical bonding behavior. In the periodic table, the elements are listed in order of increasing atomic number Z.
It is the Pauli exclusion principle that requires the electrons in an atom to occupy different energy levels instead of them all condensing in the ground state. The ordering of the electrons in the ground state of multielectron atoms, starts with the lowest energy state (ground state) and moves progressively from there up the energy scale until each of the atom’s electrons has been assigned a unique set of quantum numbers. This fact has key implications for the building up of the periodic table of elements.
The first two columns on the left side of the periodic table are where the s subshells are being occupied. Because of this, the first two rows of the periodic table are labeled the s block. Similarly, the p block are the right-most six columns of the periodic table, the d block is the middle 10 columns of the periodic table, while the f block is the 14-column section that is normally depicted as detached from the main body of the periodic table. It could be part of the main body, but then the periodic table would be rather long and cumbersome.
For atoms with many electrons, this notation can become lengthy and so an abbreviated notation is used. The electron configuration can be visualized as the core electrons, equivalent to the noble gas of the preceding period, and the valence electrons (e.g. [Xe] 6s2 for barium).
Oxidation States
Oxidation states are typically represented by integers which may be positive, zero, or negative. Most elements have more than one possible oxidation state. For example, carbon has nine possible integer oxidation states from −4 to +4.
The current IUPAC Gold Book definition of oxidation state is:
“Oxidation state of an atom is the charge of this atom after ionic approximation of its heteronuclear bonds…”
and the term oxidation number is nearly synonymous. An element that is not combined with any other different elements has an oxidation state of 0. Oxidation state 0 occurs for all elements – it is simply the element in its elemental form. An atom of an element in a compound will have a positive oxidation state if it has had electrons removed. Similarly, adding electrons results in a negative oxidation state. We have also distinguish between the possible and common oxidation states of every element. For example, silicon has nine possible integer oxidation states from −4 to +4, but only -4, 0 and +4 are common oxidation states.
Summary
| Element | Fluorine |
| Number of protons | 9 |
| Number of neutrons (typical isotopes) | 19 |
| Number of electrons | 9 |
| Electron configuration | [He] 2s2 2p5 |
| Oxidation states | -1 |
Source: www.luciteria.com
Other properties of Fluorine
