Fluorine is the most reactive element and it readily reacts with almost all elements. It is a non-metal halogen and being highly electronegative it attracts electrons towards itself.
So, does Fluorine conduct electricity? Fluorine, like other non-metals (except graphite and silicon) does not conduct electricity. It is the most electronegative atom and is very reactive because of which it only gains electrons and does not lose them. And due to this property of fluorine, it restricts the movement of electrons and fails to conduct electricity.
Non-metals are poor conductors of heat and electricity. The study of the chemical and physical nature of fluorine is important in order to understand why it can not conduct electricity.
Why is fluorine a bad conductor of electricity?
The electric conductivity in metals is due to the presence of free electrons and the flow of electrons is responsible for conducting electricity. In non-metals for example fluorine, the electron affinity and the ionization energy are maximum.
The term Electron affinity is defined as the energy released when an atom gains an electron. The higher the force of attraction between the electrons and the nucleus the higher is the electron affinity of an atom.
The higher the affinity, the higher is the amount of energy (called the ionization energy) required to detach the electrons from an isolated atom.
We know that electrons are the carriers of electricity. Fluorine is a bad conductor of electricity as it remains incapable of giving out free electrons that remain localized on fluorine.
This happens mainly due to two reasons:
- The reactivity of fluorine atom is high as it needs only one electron to fill its outermost orbit.
- The small atomic radius in fluorine helps the nucleus to potentially pull the valence electrons towards the center.
In metals, the atomic radius is bigger than in non-metals. The increased distance between the nucleus and the valence electrons weakens the force of attraction between the two and hence minimizes the electron affinity and the ionization energy.
This is the reason why metals give free ions. The valence electrons in metals are responsible for electrical conductivity.
Why is fluorine the most electronegative element?
An element is said to be electronegative if it tends to attract valence electrons towards itself. Fluorine is highly electronegative because if its own structural factors. The fluorine atom has a reduced size.
The electronegativity depends on the distance between the nucleus and the electrons residing. The atomic number of fluorine is 9 and it requires one electron to complete the octet.
The distance at which the valence electrons lie from the nucleus is minimum in the case of fluorine. This results in a strong binding between the nucleus and the valence electrons.
Let us understand the electronic configuration of fluorine.
The electronic configuration for fluorine is 1sp²2s²2p5 which shows that there are two electrons in the inner shell and seven electrons in the outer shell. The electrons in the outer shell 9-2=7 remain ineffective at shielding the nucleus and experience a nuclear charge. This affects the atom’s physical properties.
When we look at the arrangement of elements in the periodic table we come to know why fluorine is highly electronegative. As we move right along a period, the electronegativity and the ionization energy increases making the group 17 elements the most electronegative.
With the gain of electrons, the nuclear charge of the atom increases. The nucleus of fluorine shows high electron affinity and with the existing binding force between the nucleus and the valence electrons, the electronegativity increases.
Why do gases begin to conduct electricity at low pressure?
According to different studies, it is seen that at low pressure the mean free path is large and the colliding electrons or ions get enough kinetic energy and path to accelerate. At such pressure, the free electrons can move freely across the path.
More importantly, the kinetic energy of electron should be enough to ionize the other atoms which can be gained only at a low pressure where the mean free path is enough.
It is also noted that at low pressure the gases turn into plasma. the electrical conductivity is completely dependent on the mobile free ions.
Whereas at high pressure, the mean free path is comparatively low. The free electrons do not get enough space and time to get accelerated. Thus, if electrons do not get accelerated, they cannot gain enough kinetic energy to ionize other atoms.
This can be understood with an example of the neon tube light.
In this, neon gas is present inside the tube at low pressure. Both ends of the tube have an electrode. And high voltage is applied across the tube due to which the neon gas ionizes and free ions flow across the tube having enough mean free path.
Physical and chemical properties of fluorine
The physical and chemical properties of fluorine help to distinguish it from other elements on the periodic table.
- Fluorine has a pale yellow color and is a colorless gas.
- In the liquid state, it is soluble in liquid oxygen and ozone.
- It has a pungent odor and is sometimes fluorescent.
- It has an atomic mass of 18.99 u.
- It has a melting point of -219.8°C.
- The boiling point of fluorine is -188.1°C.
- It is 1.3 times denser than air.
- Fluorine does not react with oxygen.
- It is a highly poisonous or toxic at room temperature.
- Fluorine gas is highly corrosive.
- When fluorine gas is mixed with water it reacts explosively.
- Fluorine reacts with all the elements except helium, argon, and neon.
- It is a heat resistant element.
- It is highly flammable.
Industrial applications of fluorine
- Fluorine is an essential element in the nuclear energy industry.
- The Chlorofluorocarbons were once used in aerosols, refrigerators, air conditioners, food packaging, and fire extinguishers.
- It is used in the production of high-temperature resistant plastics such as Teflon.
- Fluorine is added to toothpaste in small amounts to prevent tooth decay.
- Fluorine-probes in cancer treatment are showing promise.
- Drugs having fluorine are used against issues related to the cardiovascular system and central nervous system.