2.5 Lewis Diagrams

• Lewis diagrams depict the bonding between atoms and the lone pairs of electrons
• Match the exception to the octet rule with its description:

  Odd Electron Species ↔️ Molecules with an odd number of valence electrons

  Electron Deficient Species ↔️ Central atoms lack enough electrons

  Expanded Octet Species ↔️ Central atoms exceed 8 valence electrons
• Hydrogen and helium only require 2 valence electrons to satisfy their stability


  True
• CO₂ forms double bonds between carbon and each oxygen atom to satisfy the octet rule

  True
• What is an example of an odd electron species?

  NO
• What type of bonds are present in the Lewis diagram of CO₂?

  Double bonds
• What is the definition of the octet rule?

  Atoms form compounds with 8 valence electrons
• Match the exception type with its example:

  Odd electron species ↔️ NO

  Electron deficient species ↔️ BF₃

  Expanded octet species ↔️ SF₆
• In NaCl, sodium forms a Na⁺ cation by losing one valence electron to chlorine.


  True
• In covalent compounds, atoms can be connected using single, double, or triple bonds
• In the octet rule, each atom must have 8 valence electrons, except for hydrogen which needs 2.
• What is an example of an electron deficient species?

  BF₃
• Match the concept with its significance:

  Valence electron arrangement ↔️ Determines bonding and reactivity

  Bonding between atoms ↔️ Influences molecular shape and stability

  Lone pairs ↔️ Affects molecular geometry and reactivity
• When drawing Lewis diagrams, maximize the number of covalent bonds using the remaining valence electrons.
• Expanded octet species occur because central atoms in period 3 and beyond can use available d orbitals.
• Match the exception type with its example:

  Odd electron species ↔️ ClO₂

  Electron deficient species ↔️ AlCl₃

  Expanded octet species ↔️ SF₆
• What does the octet rule state in chemistry?

  Atoms achieve 8 valence electrons
• What is the first rule for drawing Lewis diagrams?

  Determine valence electrons
• Atoms in period 3 and beyond can accommodate more than 8 valence electrons due to available d orbitals.
• Sulfur (S) can have 10 or 12 valence electrons in a compound because it has an expanded valence shell.
• Match the exception to the octet rule with its example:

  Odd Electron Species ↔️ NO

  Electron Deficient Species ↔️ BF₃

  Expanded Octet Species ↔️ SF₆
• Electron-deficient species such as BF₃ lack a complete octet
• The first step in drawing a Lewis diagram is to determine the total number of valence electrons
• Hydrogen and helium only need 2 valence electrons to achieve stability.


  True
• What is the primary difference between Lewis diagrams for ionic and covalent compounds?

  Complete electron transfer
• Steps for drawing Lewis diagrams for ionic compounds

  1️⃣ Determine the ions formed

  2️⃣ Draw individual ion structures

  3️⃣ Use brackets and charges
• What do Lewis diagrams for covalent compounds show?

  Valence electrons and bonding
• Molecules with an odd number of valence electrons can satisfy the octet rule for all atoms.

  False
• Lewis diagrams are a type of Lewis structure that only depicts valence electrons.


  True
• Expanded octet species are an exception to the octet rule.


  True
• In a Lewis diagram, all atoms must have exactly 8 valence electrons to satisfy the octet rule

  False
• What is the primary goal of the octet rule?

  Stable electron configuration
• How many valence electrons does CO₂ have?

  16
• The Lewis diagram for CO₂ shows double bonds between carbon and each oxygen atom.
• Expanded octet species can have more than 8 valence electrons around the central atom.

  True
• Steps for drawing Lewis diagrams

  1️⃣ Determine the total number of valence electrons

  2️⃣ Arrange the atoms

  3️⃣ Add lone pairs

  4️⃣ Maximize the number of covalent bonds

  5️⃣ Satisfy the octet rule
• Exceptions to the octet rule include atoms that can be stable with fewer or more than 8 valence electrons
• In ionic compounds, ions are enclosed in brackets and their charges are indicated.
• What do Lewis diagrams for covalent compounds show?

  Arrangement of valence electrons
• Key steps for drawing Lewis diagrams

  1️⃣ Determine the total number of valence electrons

  2️⃣ Arrange the atoms and form bonds

  3️⃣ Add lone pairs

  4️⃣ Satisfy the octet rule