Lewis Diagrams
How many valence electrons does carbon have, and how many bonds does it usually form in a Lewis diagram?
Carbon has 4 valence electrons
Carbon usually forms 4 bonds
What type of bond forms between Na and Cl?
Ionic bonds
What is the shape and bond angle of CH₄?
Tetrahedral (≈109.5°)
Identify the reaction type:
2H₂ + O₂ → 2H₂O
Synthesis (also combustion)
How many particles are in 1 mole?
6.02 × 10²³ particles
How many valence electrons are in NH₃, and how many lone pairs are on nitrogen?
Total valence electrons in NH₃: 8
Nitrogen: 5
Three hydrogens: 3 × 1 = 3
Total = 8 valence electrons
Lone pairs on nitrogen: 1
So, NH₃ has 8 valence electrons in total, and nitrogen has 1 lone pair.
Is the bond in H₂O polar covalent or non-polar covalent?
Polar covalent
How many electron domains are around the central atom in NH₃?
4 (3 bonds, 1 lone pair)
What type of reaction breaks one compound into simpler substances?
Decomposition
Convert 2.0 moles of CO₂ into molecules.
1.20 × 10²⁴ molecules
Which molecule has multiple valid Lewis structures (resonance)?
A) CH₄
B) CO₂
C)NH41+
D) H₂O
NH41+
Which property is typical of metallic bonding?
A) Brittle
B) Conducts electricity
C) Low melting point
D) Forms discrete molecules
Conducts electricity
Match the molecule to its hybridization:
CO₂, NH₃, CH₄
CO₂ → sp
NH₃ → sp³
CH₄ → sp³
Balance the equation:
Al + O₂ → Al₂O₃
4Al + 3O₂ → 2Al₂O₃
What is the mass of 0.50 moles of NaCl?
29.3 g
Which atom is most likely to have the greatest number of lone pairs in a stable Lewis structure?
A) Carbon
B) Nitrogen
C) Oxygen
D) Hydrogen
C) Oxygen
Rank these bonds from most ionic to most covalent:
C–H, Na–Cl, O–H
Na–Cl → O–H → C–H
Why does H₂O have a bent shape instead of linear?
Oxygen has 4 electron domains with two lone pairs which repel more strongly, creating a bent shape (~104.5°).
Identify the reaction type and balance:
C6H12 + O₂ → CO₂ + H₂O
Combustion;
C6H12 + 9O₂ → 6CO₂ + 6H₂O
How many liters of O₂ gas are produced from 2.0 moles at STP?
44.8 L
Which molecule violates the octet rule, and why?
A) BF₃
B) CO₂
C) NH₃
D) H₂O
BF₃ – incomplete octet on boron
Explain why ionic compounds conduct electricity when molten but not as solids.
Ions are only available to carry charge when they are molten and free to move
Predict the shape, bond angle, and hybridization of SO₂.
Bent shape, slightly less than 120°, sp² hybridization.
A reaction produces one product and releases a large amount of heat. What type of reaction is this and why is it common in fuels?
Synthesis; it forms very stable products and releases large amounts of energy.
A reaction requires 12 g of Mg. How many molecules of Mg is this?
3.0 × 10²³ molecules