The Lewis structure of Fluoroethane

The Lewis structure of fluorine (C2H5F) consists of two carbon atoms (C), five hydrogen atoms (H), and one fluorine atom (F). The two carbon atoms (C) are central atoms, connected by a σ bond (one σ bond equals one electron pair), while the remaining hydrogen atoms (H) and fluorine atoms (F) surround the carbon atoms and are connected by single bonds. The fluorine atom (F) has three lone pairs of electrons. This is shown in the figure below:

Steps for drawing the C₂H₅F Lewis structure

Step 1: Calculate the number of valence electrons for all atoms

According to the periodic table, carbon, hydrogen, and fluorine atoms have 4, 1, and 7 valence electrons, respectively. Therefore, the total number of valence electrons in the C2H5F molecule = valence electrons provided by 2 carbon atoms + valence electrons provided by 5 hydrogen atoms + valence electrons provided by 1 fluorine atom = 4(2) + 1(5) + 7 = 20.

Step 2: Determine the central atom

The central atom is generally the atom with the lowest electronegativity. For the Fluoroethane molecule, hydrogen atoms are generally arranged at the periphery. Carbon has a lower electronegativity than fluorine, so the carbon atom is the central atom and the other atoms are outer atoms.

Step 3: Label the lone pairs of electrons between atoms

Total valence electron pairs = total number of valence electrons/2. Therefore, for the C2H5F molecule, the total number of electron pairs is 10. The two central carbon atoms share one pair of lone pair electrons between them, while their outer peripheries each share a pair of lone pair electrons with a hydrogen atom and a fluorine atom respectively, forming a stable octet structure. To achieve a stable state for each atom, the remaining 3 lone pairs of electrons are distributed on the fluorine atom.