3-chemical-bond

iChemical Bond

  • Definition: A chemical bond is the force that holds atoms together in a chemical compound.

  • Importance: Interactions that account for the association of atoms into molecules, ions, crystals, and other species are called chemical bonding.

Ionic Bond

  • Definition: An ionic bond, also known as an electrovalent bond, is formed from the electrostatic attraction between oppositely charged ions in a chemical compound.

  • Formation:

    • Valence electrons of one atom are transferred permanently to another atom.

    • Donor atom (loses electrons) becomes a positively charged ion (cation).

    • Accepting atom (gains electrons) becomes a negatively charged ion (anion).

Periodic Table

  • Overview:

    • Organized display of chemical elements arranged by atomic number, electron configurations, and recurring chemical properties.

    • Key Groups:

      • Group 1: Alkali Metals (e.g., Lithium, Sodium)

      • Group 2: Alkaline Earth Metals (e.g., Magnesium, Calcium)

      • Transition Metals, Lanthanides, Actinides.

Properties of Elements (Metals vs Nonmetals)

  • Electronegativity:

    • Measure of how strongly atoms attract bonding electrons:

      • Metals: Low electronegativity, tend to lose electrons.

      • Nonmetals: High electronegativity, tend to gain electrons.

Noble Gases

  • Characteristics:

    • Noble gases are odorless, colorless, and nonflammable.

    • Extremely stable due to full valence electron shells.

    • Little tendency to gain or lose electrons, resulting in low chemical reactivity.

  • Examples:

    • Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), Radon (Rn).

Octet Rule

  • Definition: Atoms tend to react to achieve a full outer shell of eight electrons, leading to increased stability.

  • History: Proposed by Richard Abegg; later popularized by Gilbert N. Lewis.

Formation of Ionic Bond

  • Mechanism:

    • Involves transfer of electrons, leading to the formation of cations and anions.

    • Example: Sodium Chloride (NaCl)

    • Sodium (Na): Loses 1 electron → Na⁺

    • Chlorine (Cl): Gains 1 electron → Cl⁻

Isolectronic Species

  • Definition: Ions or atoms that have the same electron configuration as noble gases.

  • Example:

    • Sodium ion (Na⁺) is isolectronic with Neon (Ne).

    • Chloride ion (Cl⁻) is isolectronic with Argon (Ar).

Covalent Bond

  • Definition: A covalent bond is the interatomic linkage resulting from the sharing of an electron pair between two atoms.

  • Characteristics:

    • Occurs primarily between nonmetals.

Formation of Covalent Bonds

  • Single Covalent Bond:

    • Example with Hydrogen (H₂): Two hydrogen atoms share one electron pair.

    • Result: Each H atom is isolectronic with Helium (He).

  • Double Covalent Bond:

    • Example with Oxygen (O₂): Two oxygen atoms share two pairs of electrons.

    • Result: Each O atom becomes isolectronic with Neon (Ne).

  • Triple Covalent Bond:

    • Example with Nitrogen (N₂): Two nitrogen atoms share three pairs of electrons.

    • Result: Each N atom becomes isolectronic with Neon (Ne).