Covalent and Polar Covalent Bonding

Covalent Bonding: Sharing Valence Electrons

• Covalent Bonding Introduction

  • Unlike ionic bonding, where valence electrons are transferred, covalent bonding involves the sharing of valence electrons between atoms.

  • This sharing allows both atoms to achieve a full valence shell, leading to greater stability.

  • Shared valence electrons are not stationary; they move around and spend time around both bonded atoms.

• Oxygen Gas ( $O_{2}$ ) Example: Nonpolar Covalent Double Bond

  • Atomic Number of Oxygen: Approximately $8$.

  • Electron Configuration: Oxygen has $2$ electrons in its first shell and $6$ valence electrons in its outermost shell.

  • Valence Shell Completeness: An oxygen atom by itself has an incomplete valence shell, needing $2$ more electrons to reach a stable octet (a full shell of $8$).

  • Interaction between two Oxygen Atoms:

    • When two oxygen atoms bond, their electronegativity (electron-attracting capability) is identical because they are the same element.

    • To achieve a full valence shell, each oxygen atom shares two pairs of its valence electrons with the other.

    • This results in both oxygen orbitals effectively having $8$ electrons at any given time due to the sharing.

  • Notation for Double Bond:

    • The sharing of two pairs of electrons is represented by a double bond, symbolized by two parallel lines, similar to an equal sign ( $=$ ).

    • Example: $O=O$

    • Each line represents a chemical bond, which is a shared pair of electrons.

  • Covalent Bond Definition: This type of bonding, where valence electrons are shared, is called a covalent bond.