Fluorine is a highly toxic diatomic gaseous compound represented by the chemical formula F2. This lightest halogen is a pale yellow-green gas with a pungent odor at room temperature.
Fluorine is the most reactive and electronegative element in the Periodic Table. The small amounts of fluorine present in the natural water protect our teeth from dental decay.
In this article, we will discuss the polarity of fluorine (F2). So, is F2 polar or non-polar? Continue reading to find out.
Is F2 polar or non-polar?
Fluorine (F2) is a non-polar molecule. The F-F bond in the F2 molecule is non-polar due to no electronegativity difference between the bonded atoms.
As the F2 molecule contains two same atoms and there is no difference in electronegativity between the two atoms, the electronic charge is evenly distributed over the molecule.
Due to this, the F-F bond in the F2 molecule is non-polar and possesses no dipole moment value.
Thus, the symmetric, linear F2 molecule is non-polar with a net dipole moment equal to 0.
A molecule with an equal charge distribution between different centers of bonded atoms is a non-polar molecule.
It is formed by the covalent bond between two same atoms leading to a symmetric electron density in the molecule overall, such as the F2 molecule.
In the case of asymmetric molecules, If the dipole moments of individually polar bonds are canceled, the molecule will be non-polar.
Hence, a non-polar molecule has an equal distribution of the electronic charge. Contrarily, if the electronic charge is not evenly distributed over the molecule, in that case, it will be a polar molecule.
The following three factors influence the polarity of any covalent molecule:
Electronegativity.
Dipole moment.
Molecular geometry or shape.
How do these factors lead to the non-polar nature of the fluorine (F2) molecule? Let’s find out.
Factors affecting the polarity of F2
Electronegativity
It is defined as the ability of an atom to attract a shared pair of electrons from a covalent chemical bond.
Electronegativity decreases down the group in the Periodic Table of elements while it increases across a period.
It is directly related to the polarity of any molecule. The greater the difference in electronegativity between atoms in a molecule, the higher will be the bond polarity.
Fluorine belongs to group VII-A (or 17) of the Periodic Table. The electronic configuration of fluorine is 1s22s22p5, so it has 7 valence electrons for bonding.
The two F atoms thus form a single covalent bond with each other to complete their octet configuration in the F2 molecule.
One valence electron consumed in bonding out of the seven initially available leaves behind six valence electrons, i.e., three lone pairs of electrons on each F atom in the F2 molecule.
Atom
Electronic configuration
Valence electrons
Fluorine (9F)
1s22s22p5
7
According to Pauling’s electronegativity scale, a molecule is non-polar if there is an electronegativity difference of 0 units between the bonded atoms.
Fluorine is the most electronegative atom in the Periodic Table (E.N = 3.98). There is no difference in electronegativity between the same bonded atoms in the F2 molecule.
Due to the zero electronegativity difference, there is a uniform electronic charge distribution in the F2 molecule overall. As a result, no charged poles are developed in the F2 molecule.
Thus, the F-F bond is non-polar in the F2 molecule.
Dipole Moment
The dipole moment is the product of electrical charge (Q) and bond length (r) between two bonded atoms. It is a vector quantity expressed in Debye (D) units.
It is represented by a Greek symbol µ and measures the polarity of a bond.
The dipole moment of any molecule depends on the difference in electronegativity between the bonded atoms. The greater the electronegativity difference, the higher the bond polarity, resulting in a high dipole moment value.
It points from the partial positive (δ+) center to the partial negative (δ–) center of a bond or molecule.
As the F2 molecule constituents the atoms of the same element (F), there is no difference in electronegativity between the bonded atoms. Due to this, the net dipole of the F-F bond is zero in the F2 molecule.
As a result of the zero dipole moment of the F-F bond, the F2 molecule is non-polar.
Molecular geometry
As discussed earlier, a fluorine (F2) molecule consists of a single F-F covalent bond. The overall molecule consists of a total of 14 valence electrons. There are three lone pairs of electrons on each F atom.
The molecule adopts a linear shape to minimize the repulsion effects due to the lone pairs on each F atom. There is a bond angle of 180 degrees.
Due to no electronegativity difference between the bonded atoms, the F-F bond has no dipole moment value in the fluorine (F2) molecule. There is an equal charge distribution over the molecule.
Thus, fluorine (F2) is a non-polar molecule with a zero dipole moment.
Difference between polar and nonpolar?
Polar molecule
Non-polar molecule
Atoms must have a difference in
electronegativity
Atoms may have the same or different electronegativity values
Unequal charge distribution overall
Equal charge distribution overall
Net dipole moment greater than zero
Net dipole moment equals to zero
Examples include water (H2O), ethanol (CH3CH2OH), ammonia (NH3), sulfur dioxide (SO2), bromine trifluoride (BrF3), nitric oxide (NO), bromine pentafluoride (BrF5), etc.
Examples include oxygen (O2), nitrogen (N2), fluorine (F2), methane (CH4), sulfur trioxide (SO3), etc.
Vishal Goyal is the founder of Topblogtenz, a comprehensive resource for students seeking guidance and support in their chemistry studies. He holds a degree in B.Tech (Chemical Engineering) and has four years of experience as a chemistry tutor. The team at Topblogtenz includes experts like experienced researchers, professors, and educators, with the goal of making complex subjects like chemistry accessible and understandable for all. A passion for sharing knowledge and a love for chemistry and science drives the team behind the website. Let's connect through LinkedIn: https://www.linkedin.com/in/vishal-goyal-2926a122b/
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