Conditions for Writing the Lewis Dot Structures
Lewis Dot structure can easily explain the formation of the covalent bonds between two molecules. Some points we must remember for drawing Lewis Dot Structures are,
- Covalent bonds are formed only when the electron pair is shared between two atoms.
- Two electrons or one electron pair constitute a single covalent bond in which each atom shares one electron.
- The sharing between atoms occurs to satisfy the Octet state of the Valence Shell. Octet rule states that an element’s stability is achieved only when it has 8 electrons in its outermost shell (except for the hydrogen atom which achieves its stability with 2 electrons in its outermost shell)
For Example, In the formation of an H2O molecule Hydrogen atom has one electron in its outermost shell and oxygen has six electrons in its outermost shell when two electrons of oxygen form a bond with two hydrogen atoms its octet is completed. Similarly, the stability of Hydrogen atoms is also achieved.
Covalent Bond
A covalent bond is formed when two atoms exchange one or more pairs of electrons. Both the atomic nuclei of the shared atom together attract these electrons. When the difference between the electronegativities of two atoms is too small for an electron transfer to take place to create ions, a covalent bond is formed. Bonding electrons are collectively referred to as the electrons that are present between the two nuclei. The “bond” that holds the atoms in molecular units together is the bound pair.