Covalent Compounds and Polyatomic Ions Study Notes

Covalent Compounds and Polyatomic Ions Overview

  • Naming Covalent Molecules

    • Covalent molecules are designated using specific prefixes to indicate the number of atoms of each element in a compound.
    • If no prefix is present, it is implied that there is only one atom of that particular element in the compound.
    • Common prefixes include:
    • mono = 1
    • di = 2
    • tri = 3
    • tetra = 4
    • penta = 5
    • hexa = 6

  • Lewis Dot Structures (LDS)

    • A Lewis Dot Structure illustrates the bonding between atoms and the lone pairs of electrons present in a molecule.
    • The general format includes:
    • ABX (where A represents the central atom, B represents the surrounding atoms, and X denotes the number of bonds).
    • The structure indicates both bonded pairs and non-bonded pairs of electrons.

Example Compounds

  1. Carbon Tetrabromide (CBr₄)

    • General Formula: CBr₄
    • Central Atom: Carbon (C)
    • Total #bonds: 4
    • Non-bonded pairs on central atom: 0
    • Total Valence Electrons: 32
    • Lewis Structure:
      • C – Br

  2. Sulfate Ion (SO₄²⁻)

    • General Formula: SO₄²⁻
    • Central Atom: Sulfur (S)
    • Total #bonds: 6
    • Non-bonded pairs on central atom: 0
    • Total Valence Electrons: 24
    • Lewis Structure:
      • S=O

  3. Hydrogen Sulfide (H₂S)

    • General Formula: H₂S
    • Central Atom: Sulfur (S)
    • Total #bonds: 2
    • Non-bonded pairs on central atom: 4

  4. Bromine Trichloride (BrCl₃)

    • General Formula: BrCl₃
    • Central Atom: Bromine (Br)
    • Total #bonds: 3
    • Non-bonded pairs on central atom: 0
    • Total Valence Electrons: 22

  5. Nitrate Ion (NO₃⁻)

    • General Formula: NO₃⁻
    • Central Atom: Nitrogen (N)
    • Total #bonds: 4
    • Non-bonded pairs on central atom: 0
    • Total Valence Electrons: 18

  6. Xenon Tetrafluoride (XeF₄)

    • General Formula: XeF₄
    • Central Atom: Xenon (Xe)
    • Total #bonds: 8
    • Non-bonded pairs on central atom: 2
    • Total Valence Electrons: 28

  7. Phosphorus Trifluoride (PF₃)

    • General Formula: PF₃
    • Central Atom: Phosphorus (P)
    • Total #bonds: 3
    • Non-bonded pairs on central atom: 1
    • Total Valence Electrons: 26
  • Credit Requirement
    • Students must complete at least 90% of the worksheet to earn credit for the worksheet.