2.2.2 Molecular Shapes

• Steps to determine electron pair geometry using VSEPR theory:

  1️⃣ Identify the central atom

  2️⃣ Count the number of electron pairs

  3️⃣ Arrange electron pairs for minimum repulsion
• Match the total electron pairs with the corresponding electron pair geometry:

  2 ↔️ Linear

  3 ↔️ Trigonal Planar

  4 ↔️ Tetrahedral
• Covalent bonding involves the sharing of electrons
• What does the octet rule state regarding electron configurations?

  Full outer shell of eight electrons
• Carbon achieves the octet rule by sharing electrons in covalent bonds.
• Arrange the following molecular shapes by increasing bond angle:

  1️⃣ Bent

  2️⃣ Trigonal Pyramidal

  3️⃣ Tetrahedral

  4️⃣ Trigonal Planar

  5️⃣ Linear
• In a $H_{2}$ molecule, each hydrogen atom shares one electron
• Nitrogen achieves the octet rule by gaining three electrons.
• What is the primary principle of VSEPR theory?

  Minimizing electron pair repulsion
• Match the molecular shape with its bond angle:

  Linear ↔️ 180°

  Trigonal Planar ↔️ 120°

  Tetrahedral ↔️ 109.5°

  Bent ↔️ <109.5°
• Match the molecular shape with its bond angle:

  Linear ↔️ 180°

  Trigonal Planar ↔️ 120°

  Tetrahedral ↔️ 109.5°
• VSEPR theory minimizes repulsion between electron pairs around a central atom.
• Electron pairs, both bonding and lone pairs, repel
• Lone pairs exert stronger repulsion than bonding pairs.
• What is the electron pair geometry of ammonia (NH_{3}</latex>)?

  Tetrahedral
• Molecular shapes are determined by minimizing repulsion between electron pairs.
• The presence of lone pairs causes greater repulsion
• Match the molecular shape with its bond angles:

  Linear ↔️ 180°

  Trigonal Planar ↔️ 120°

  Tetrahedral ↔️ 109.5°
• Lone pairs reduce bond angles compared to ideal values.
• Covalent bonding involves the sharing of electrons
• The octet rule states that atoms share electrons to achieve eight valence electrons.
• Lone pairs exert stronger repulsion
• Steps to determine electron pair geometry using VSEPR theory:

  1️⃣ Identify the central atom

  2️⃣ Count the number of bonding and lone pairs

  3️⃣ Match the electron pair count to the geometry
• What do bonding and lone pairs repel in molecules?

  Each other
• Electron pairs in molecules arrange to maximize separation and minimize repulsion.
• Lone pairs exert stronger repulsion
• What is the bond angle in a linear molecular shape?

  180°
• What is the bond angle in a trigonal planar molecular shape?

  120°
• The bond angle in a tetrahedral shape is 109.5°
• The bond angle in a trigonal pyramidal shape is less than 109.5°.
• Match the electron pair geometry with its example molecule:

  Linear ↔️ $BeCl_{2}$

  Trigonal Planar ↔️ $BF_{3}$

  Tetrahedral ↔️ $CH_{4}$

  Trigonal Bipyramidal ↔️ $PCl_{5}$
• What is the first step in determining the electron pair geometry of a molecule using VSEPR theory?

  Identify the central atom
• Steps to determine electron pair geometry using VSEPR theory:

  1️⃣ Identify the central atom

  2️⃣ Count bonding pairs and lone pairs

  3️⃣ Match the electron pair count to geometry
• Ammonia $(NH_{3})$ has a tetrahedral electron pair geometry
• What should you count after identifying the central atom in VSEPR theory?

  Bonding pairs and lone pairs
• Match the electron pair geometry with its example molecule:

  Trigonal Bipyramidal ↔️ $PCl_{5}$

  Octahedral ↔️ $SF_{6}$
• What theory is used to predict molecular shapes by minimizing repulsion between electron pairs?

  VSEPR theory
• Lone pairs cause greater repulsion than bonding pairs, reducing bond angles
• Common molecular shapes include linear, trigonal planar, and tetrahedral
• Match the molecular shape with its bond angle:

  Linear ↔️ 180°

  Trigonal Planar ↔️ 120°

  Tetrahedral ↔️ 109.5°