Hydrogen Iodide (HI) Lewis Structure

Lewis structure of Hydrogen iodide (HI) contains only one H-Br bond. There are no charges on atoms in HI lewis structure because HI is a neutral molecule. There is three lone pairs on bromine atom in HI molecule. HI is a very easy lewis structure to draw due to its simplicity.


HI lewis structure

HI hydrogen iodide lewis structure

There are only one hydrogen atom and one iodine atom in HI molecule. In the lewis structure of HI, hydrogen atom has made a single bond with iodine atom.



Steps of drawing lewis structure of HI

When we draw a lewis structure, there are several steps to follow. Number of steps can be changed according the complexity of the molecule or ion. Because HI molecule is a simple, and there is no overall charge, all of these steps are not required to use to complete the lewis structure. However those all steps are mentioned and explained in detail in this tutorial for your knowledge.

  1. Find total number of electrons of the valance shells of hydrogen atom and iodine atom
  2. Total electrons pairs existing as lone pairs and bonds
  3. Center atom selection
  4. Mark lone pairs on atoms
  5. Mark charges on atoms if there are charges.
  6. Check the stability and minimize charges on atoms by converting lone pairs to bonds to obtain best lewis structure.

Total number of electrons of the valance shells of HI

There are two elements in hydrogen iodide; hydrogen and iodine. Hydrogen is a group IA element in the periodic table and only has one electron in its last shell (valence shell). Iodine is a group VIIA element in the periodic table and contains seven electrons in its last shell. Now, we know how many electrons are there in valence shells of hydrogen and bromine atoms.


  • valence electrons given by hydrogen atom = 1 * 1 = 1
  • valence electrons given by iodine atom = 7 * 1 = 7

  • Total valence electrons = 1 + 7 = 8


Total valence electrons pairs

Total valance electrons pairs = σ bonds + π bonds + lone pairs at valence shells

Total electron pairs are determined by dividing the number total valence electrons by two. For, HI, Total pairs of electrons are four in their valence shells.



Center atom of HI molecule

Because, there are only two elements in HI molecule, we do not need to worry about finding the center atom. Therefore, we can draw the skeleton of HI easily.

HI skeleton

Lone pairs on atoms

After determining the center atom and sketch of HI molecule, we can start to mark lone pairs on atoms. Remember that, there are total of four electron pairs.

  • There is already one bond in the drawn skeleton.
  • Usually, those remaining electron pairs should be started to mark on outside atoms. But in HI, there are only two atoms and hydrogen atom cannot keep more than two electron in its last shell. There are already two electrons in hydrogen atom. Therefore, we cannot mark those remaining electrons pairs on hydrogen atom.
  • Therefore, mark those remaining three electrons pairs on iodine atom. Iodine atom will take three lone pairs to fulfill the octal.
mark  lone pairs on atoms in HI

Mark charges on atoms

There are no charges on hydrogen atom and iodine atom. Also, remember that HI is a molecule which does not have a charge. Therefore, not having charges on every atoms tells us we have drawn a stable structure.



Check the stability and minimize charges on atoms by converting lone pairs to bonds

Because there are no charges on atoms, no need to worry about reducing charges as a step of obtaining the best lewis structure. Therefore, we have already got the best lewis structure for HI.



Questions