HF Lewis structure

HF (hydrogen fluoride) has one hydrogen atom and one fluorine atom.

In the HF Lewis structure, there is a single bond between the hydrogen and fluorine atoms, and on the fluorine atom, there are three lone pairs.

Alternative method: Lewis structure of HF

Rough sketch

• First, determine the total number of valence electrons

In the periodic table, hydrogen lies in group 1, and fluorine lies in group 17.

Hence, hydrogen has one valence electron and fluorine has seven valence electrons.

Since HF has one hydrogen atom and one fluorine atom, so…

Valence electrons of one hydrogen atom = 1 × 1 = 1
Valence electrons of one fluorine atom = 7 × 1 = 7

And the total valence electrons = 1 + 7 = 8

Learn how to find: Hydrogen valence electrons and Fluorine valence electrons

• Second, find the total electron pairs

We have a total of 8 valence electrons. And when we divide this value by two, we get the value of total electron pairs.

Total electron pairs = total valence electrons ÷ 2

So the total electron pairs = 8 ÷ 2 = 4

• Third, determine the central atom

Here hydrogen can not be the central atom. Because the central atom is bonded with at least two other atoms, and hydrogen has only one electron in its last shell, so it can not make more than one bond.

Hence, here we have to assume that the central atom is fluorine.

• And finally, draw the rough sketch

Lone pair

Here, we have a total of 4 electron pairs. And one H — F bond is already marked. So we have to only mark the remaining three electron pairs as lone pairs on the sketch.

Also remember that hydrogen is a period 1 element, so it can not keep more than 2 electrons in its last shell. And fluorine is a period 2 element, so it can not keep more than 8 electrons in its last shell.

Always start to mark the lone pairs from outside atoms. Here, the outside atom is fluorine.

So for fluorine, there are three lone pairs, and for hydrogen, there is zero lone pair because all three electron pairs are over.

Mark the lone pairs on the sketch as follows:

Formal charge

Use the following formula to calculate the formal charges on atoms:

Formal charge = valence electrons – nonbonding electrons – ½ bonding electrons

For hydrogen atom, formal charge = 1 – 0 – ½ (2) = 0

For fluorine atom, formal charge = 7 – 6 – ½ (2) = 0

Here, both hydrogen and fluorine atoms do not have charges, so no need to mark the charges.

Final structure

The final structure of HF contains a central fluorine atom connected to a single hydrogen atom through a covalent bond. In this configuration, the fluorine atom satisfies the octet rule by maintaining three lone pairs alongside its single shared bond, while the hydrogen atom achieves its stable duet state. This arrangement represents the most stable state for the molecule because it results in a formal charge of zero for both the hydrogen and the fluorine atom. Accordingly, this specific electronic distribution serves as the definitive and most accurate Lewis representation of hydrogen fluoride.

Next: SCl₂ Lewis structure

External video

• Lewis Dot Structure for HF (Hydrogen fluoride or Hydrofluoric acid) – YouTube • Wayne Breslyn

External links

• https://techiescientist.com/hf-lewis-structure/
• https://www.thegeoexchange.org/chemistry/bonding/Lewis-Structures/HF-lewis-structure.html
• https://lambdageeks.com/hf-lewis-structure/
• https://sciedutut.com/hf-lewis-structure/