Chemical bonding

Atomic Structure and Stability

• The outer shell of many atoms, with the exception of hydrogen, can hold eight electrons.

• Atoms that possess eight electrons in their outer shell are deemed chemically stable.

• This stability conforms to what is known as the octet rule.

• Atoms can give up, accept, or share electrons to achieve a complete octet in their outer shells when they combine to form compounds.

Chemical Bonding

Covalent Bonding

• A covalent bond is created when atoms share electrons to satisfy the octet rule.

  • Example:

  • A carbon atom has four electrons in its outer shell.

  • To achieve stability, carbon needs four more electrons for a total of eight.

  • By sharing electrons with four hydrogen atoms, carbon can complete its outer shell with eight electrons.

  • In this configuration, each hydrogen atom shares the bond and achieves two electrons in its outer shell, which is stable for hydrogen.

Ionic Bonding

• An ionic bond forms when two atoms are bonded by the electrostatic attraction between their opposite charges.

  • Example:

  • The interaction between sodium (Na) and chlorine (Cl) demonstrates ionic bond formation.

  • Sodium has one electron in its third shell and is likely to give up this electron:

    • Losing this electron leaves sodium with eight electrons in the remaining outer shell, resulting in a slightly positive charge for the sodium ion (Na⁺).

  • Chlorine, conversely, has seven electrons in its outer shell and tends to gain one electron:

    • Upon gaining an electron, chlorine achieves a full outer shell, resulting in a slightly negative charge (Cl⁻).

  • The charged atoms, sodium and chlorine, are termed ions.

  • Ions of opposing charges (Na⁺ and Cl⁻) attract each other, resulting in the formation of ionic bonds.

Formation of Sodium Chloride

• The resulting ionic bond between sodium and chlorine produces a molecule known as sodium chloride (NaCl), commonly referred to as table salt.