University:
University of North Carolina at Charlotte
Course:
CHEM 1251 | General Chemistry I
Academic year:

2024
Views:

335

Pages:

8
Author:

Kamila P.

Lewis Structures: PBr₅: :Br-P-Br: COCl₂: :O=C=Cl: CHCl₃: H-C-Cl: SF₄: F-S-F: XeF₂: :F-Xe-F: PF₅: F-P-F: Note: Valence Shell Expansion: Atoms of elements in period 3 and higher can sometimes fit more than eight valence electrons around them. For sulfur, xenon, and phosphorus, the remaining two electrons are placed in the central atom. Chemical Formulas and Structures: (CIF₃): Chlorine trifluoride (CIF₅): Chlorine pentafluoride (CH₃OH): Methanol (C₃H₈): Propane (CH₃CHO): Acetaldehyde Lewis Structures: For each molecule, the Lewis structure is drawn using dots to represent valence electrons and lines to represent bonds. Expanded Octets: Elements in period 3 or higher can have more than eight valence electrons. These elements can expand their octets to accommodate additional electrons. Examples: Arsenic pentachloride (AsCl₅) Sulfur hexafluoride (SF₆) Lewis Structures: For AsCl₅ and SF₆, the Lewis structures are drawn with expanded octets around the central atoms. Practice Problems: XeF₂: Lewis structure: F-Xe-F Formal charges: Xe = 2, F = -1 KrF₄: Lewis structure: F-Kr-F Formal charges: Kr = 2, F = -1 SO₃: Lewis structures: O=S=O (resonance structures) Formal charges: S = 0, O = 0 Perchlorate ion (ClO₄⁻): Lewis structure: O-Cl-O Formal charges: Cl = 0, O = -1 Note: The best Lewis structure is the one that minimizes the formal charges on all atoms. Hybridization of Central Atoms: Sulfur hexachloride (SCl₆): sp³d² Phosphorus trichloride (PCl₃): sp³ Borate ion (BO₃⁻): sp² Polarity of Molecules: CCl₄: Nonpolar CH₂O: Polar (Oxygen) PCl₃: Nonpolar CH₄: Nonpolar H₂O: Polar (Oxygen) NH₃: Polar (Nitrogen) H₂S: Polar (Sulfur) CClH₃: Nonpolar C₂H₂: Nonpolar BeH₂ molecule: Number of electron groups around central Be atom: 2 Electron domain geometry: Linear Lewis structure: H-Be-H PCl₃ molecule: Number of electron groups around central P atom: 4 Electron domain geometry: Tetrahedral Lewis structure: Cl-P-Cl NO₃⁻ molecule: Number of electron groups around central N atom: 3 Electron domain geometry: Trigonal planar Lewis structure: O-N-O ICl₄⁻ anion: Shape: Square planar Bond angle: 90° PCl₅: Lewis structure: Cl-P-Cl SeCl₄: Lewis structure: Cl-Se-Cl XeF₂: Lewis structure: F-Xe-F Molecular geometry: Linear Bond angle: 180° H₂O: Lewis structure: H-O-H Molecular geometry: Bent Bond angle: 104.5° NH₃: Lewis structure: H-N-H Molecular geometry: Trigonal pyramidal Bond angle: 107° BrO₃⁻: Lewis structure: O-Br-O Molecular geometry: Trigonal planar Bond angle: 120° CH₄: Lewis structure: H-C-H Molecular geometry: Tetrahedral Bond angle: 109.5° CH₂Cl₂: Lewis structure: Cl-CH₂-Cl Molecular geometry: Tetrahedral Bond angle: 109.5° CHCl₃: Lewis structure: Cl-CHCl-Cl Molecular geometry: Tetrahedral Bond angle: 109.5° CCl₄: Lewis structure: Cl-C-Cl Molecular geometry: Tetrahedral Bond angle: 109.5° Other structures: [O-Br-O]⁻ [H-C-H] [H-O-H] [H-N-H] Hybridization: CH₄: sp³ hybridization, 4 sigma bonds, 1 lone pair CNO⁻: sp hybridization, 2 sigma bonds, 2 pi bonds Bond Lengths: H-F < H-Cl < H-Br < H-I