Lewis structure of Hydrogen peroxide (H2O2) contains two O-H bonds and one O-O bond. Also, there are two lone pairs on each oxygen atom. Concept of number of total valence electrons of oxygen and hydrogen atoms are used to draw lewis structure of H2O2. Each step of drawing lewis structure of H2O2 is explained in detail in this tutorial.
There are two hydrogen atoms and two oxygen atoms in H2O2. A hydrogen atom is made a bond with one oxygen atom. There is a single bond between two oxygen atoms and each oxygen atom has two lone pairs.
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 H2O2 molecule is a simple molecule and there is no overall charge, some of these steps are not required to use. However those all steps are mentioned and explained in detail in this tutorial.
Important: Drawing correct lewis structure is important to draw resonance structures correctly.
There are two kind of elements in hydrogen peroxide; hydrogen and oxygen. Hydrogen is a group IA element in the periodic table and only has one electron in its last shell (valence shell). Oxygen is a group VIA element in the periodic table and contains six electrons in its last shell. Now, we know how many electrons are there in valence shells of hydrogen and oxygen atoms.
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, H2O2, Total pairs of electrons are seven in their valence shells.
To be the center atom in a molecule, ability of having greater valance is important. Then, from hydrogen and oxygen atoms, which atom has the highest valence? We know, it is oxygen. Maximum valence of oxygen is two as explained earlier. Hydrogen's only valence is one. Therefore, oxygen atom should be the center atom of H2O2. So, we can construct the sketch of H2O2 as below. This sketch shows how atoms are connected with each other in the H2O2 molecule.
After determining the center atom and sketch of H2O2 molecule, we can start to mark lone pairs on atoms. Remember that, there are total of seven electron pairs.
There are no charges on oxygen atoms and hydrogen atoms. Also, remember that H2O2 is a molecule which does not have a charge. Therefore, not having charges on every atoms tells us we have drawn the lewis structure to a good level. But, we need to make sure, this is the best structure.
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 H2O2.