Covalent
Bonding
Covalent bonding is a form of chemical bond that involves
the sharing of electron pairs between atoms. This
connection occurs when atoms with similar
electronegativities come together and contribute one or
more electrons to be shared in a bond, allowing both atoms
to acquire a full outer electron shell and hence increased
stability.
Diagram
Explanation
To obtain a full outer shell, oxygen
requires 8 electrons, but only has 6,
whereas hydrogen requires 2 but only has
1. By sharing electrons with two hydrogen
atoms, oxygen forms a full outer shell, as
do the hydrogen atoms.
Single, Double, and Triple Bonds
Covalent bonds can vary in the number of shared electron pairs
Single Bond
One pair of electrons is shared (e.g., H₂, Cl₂).
Double Bond
Two pairs of electrons are shared (e.g., O₂, CO₂).
Triple Bond
Three pairs of electrons are shared (e.g., N₂, C₂H₂).
Key points
Bond strength
& length
The more electron pairs that are shared, the stronger the bond.
As the number of shared electrons increases, the bond length
decreases.
Non- polar
covalent bond
If the atoms sharing electrons have similar electronegativities
(such as in H₂ or O₂), the electrons are shared equally.
Polar covalent
bond
If one atom is more electronegative than the other, the electrons
are not shared equally, creating a partial positive charge on one
atom and a partial negative charge on the other.
Electron
sharing
In covalent bonds, atoms share electrons to fill their outer
(valence) electron shells, usually aiming for the electron
configuration of a noble gas.