In the Lewis electron dot structure for O2, how many additional dots (electrons) should be shown around each O atom?
The Correct Answer and Explanation is :
In the Lewis electron dot structure for O₂ (dioxygen), each oxygen atom should have two additional dots (electrons) around it.
To understand this, let’s break it down step by step.
Understanding Valence Electrons
Oxygen is in Group 16 of the periodic table, which means it has six valence electrons. In a Lewis dot structure, we represent these valence electrons as dots around the atomic symbol. For a single oxygen atom, we would represent its six valence electrons as follows:
..
:O:
..Here, the dots (or pairs of dots) represent the valence electrons that are available for bonding.
Diatomic Oxygen (O₂)
When two oxygen atoms bond to form O₂, they share electrons to achieve a full outer shell. The ideal electron configuration for oxygen is to have eight electrons in its outer shell (the octet rule). In the case of O₂, the two oxygen atoms form a double bond, sharing four electrons (two pairs).
Drawing the Lewis Structure for O₂
- Count the Total Valence Electrons: Each oxygen has six valence electrons, so for two oxygen atoms, we have a total of 12 valence electrons.
- Forming Bonds: The two oxygen atoms will share two pairs of electrons, forming a double bond. This uses four of the total valence electrons (2 from each oxygen).
- Distributing Remaining Electrons: After accounting for the bonding electrons, we have 8 valence electrons left (12 total – 4 used in bonding = 8). Each oxygen atom will then have 4 additional electrons (2 lone pairs) around it:
..
:O=O:
..Final Representation
In the final Lewis structure, each oxygen atom effectively has 8 electrons around it: 4 shared (in the double bond) and 4 additional electrons (2 lone pairs). Therefore, each oxygen atom has 2 additional dots (electrons) shown around it, signifying the electrons involved in the double bond and those remaining as lone pairs.
This representation emphasizes how the sharing of electrons allows each atom to attain a stable electron configuration, fulfilling the octet rule.