What is Lewis Structure?
The Lewis Structure or the Lewis Dot Diagram or the Lewis Dot Structure, named after Gilbert N. Lewis, shows the pictorial representation of the atomic bonding of the molecules or an element. It shows the lone pairs of molecules that are existing in a molecule. A Lewis Structure can be drawn or represented both in case of the covalently bonded molecule and for the coordination of compounds. Lewis dot structure is an illustrated representation of the arrangement of the valence shell electrons in the molecule. These valence electrons are symbolized by drawing dots around the individual atoms hence the Lewis dot structure. Drawing lines symbolizes the bonds formed in the molecule.
Lewis Structure of Ammonia (NH3)
The Lewis structure of ammonia, (NH3) would be three hydrogen atoms which are bonded to a nitrogen atom in the middle with one lone pair of electrons on top of the atom. As ammonia can donate those electrons this is the reason why ammonia acts as a Lewis base .
Ammonia has total 4 regions of electron density around the central nitrogen atom (3 bonds and a lone pair). These are arranged in a tetrahedral shaped manner. The molecular shape is trigonal pyramidal with H-N-H angles of 106.7°.
Lewis structure of methane (CH4)
Forming the Lewis structure for CH4 requires only single bonds. It is one of the easiest Lewis structures to draw.
Remember that hydrogen atoms is always drawn on the outside of a Lewis structure and they only need two valence electrons for a full outer shell.
Lewis Dot Structure also explains some of the basic properties of this particle. Since there are no lone pairs on the central atom there are few dipoles created and the minimum electronegativity difference means that these bonds can vitally be treated as non polar covalent bonds. This means that all attractive forces inside the molecule depend on weak London Dispersion Forces which only strengthen in far larger atoms.
Lewis Structure of Carbon dioxide (CO2)
In Carbon dioxide molecule, there are two oxygen atoms and one carbon atom. The Carbon atom is in the molecule least electronegative so it is in the central position. Two Oxygen atoms are located on the corner extreme where both these atoms share electrons and form bonds with the central Carbon atom.
To understand the bond formation and the arrangement let’s go through the valence electrons of all the present atoms in the molecule.
Valence electrons in Carbon are: 4
Valence electrons in Oxygen are: 6 by 2 = 12 ( as there are two Oxygen atoms in the molecule so we will multiply it by 2)
Total number of valence shell electrons in the molecule = 16
We can say that Carbon Dioxide has a linear molecular geometry. It has sp hybridization and it has bond angles of 180 degrees. There are no lone pairs of electrons in the molecule and there is a uniform distribution of the electrons in its structure. Due to the present repulsive forces between the pairs of electrons carbon dioxide (CO2) takes up linear geometry.
Lewis structure of N2
2N or N2, are basically two forms of the element which are the same.
There is a minor difference between both of the two. 2N refers to two molecules of the Nitrogen atom, and N2 states that two atoms of Nitrogen which are present in a single molecule. The number written at the starting, refers to the number of molecules and the number written in the subscript refers to the numbers of atom present. In order to know this answer you first need to know the number of valence electrons present in Nitrogen.
Since Nitrogen belongs to the diatomic molecule in the VA group family on the periodic tables, which means that the valency of the molecule is five therefore, it needs three more valences of electrons in order to complete its octet which contains 8 electrons, and therefore nitrogen is a triple bonded molecule.
The Nitrogen atom, therefore, completes its octet by sharing three electrons of another nitrogen atom, with the triple bonds or the covalent bonds and thus it creates, N2 that is two atoms or diatoms in a single Nitrogen molecule. Since Nitrogen is a member of the Group 5A (which based on the periodic table), the number of electrons in its outermost shell must be five. The total number of valence electrons between the two N atoms is 10 electrons.