AP Chemistry Flashcards: Lewis Diagrams

What this deck covers

This deck focuses on Lewis Diagrams, giving you a quick way to review the definitions, rules, and examples that matter most for AP Chemistry.

How to use these flashcards

Work through these flashcards in short sessions. Try to answer each prompt before flipping the card, then revisit any cards you miss until the explanation feels automatic.

Flashcard 1: Identify the Lewis Diagram for sulfur dioxide ($SO_2$).

Answer: O=S-O with one lone pair on S and two on each O. Bent structure due to lone pair repulsion on sulfur.

Flashcard 2: What is the Lewis Diagram for sulfur hexafluoride ($SF_6$)?

Answer: F-S-F with four additional F atoms bonded to S. Octahedral structure utilizing sulfur's expanded octet.

Flashcard 3: What is the Lewis Diagram for ethylene ($C_2H_4$)?

Answer: H-C=C-H with additional H atoms bonded to each C. Planar molecule with carbon-carbon double bond.

Flashcard 4: How many lone pairs are on the oxygen in water's Lewis Diagram?

Answer: Two lone pairs. Oxygen has 6 valence electrons, forms 2 bonds, leaves 4 as lone pairs.

Flashcard 5: What is the Lewis Diagram for phosphine ($PH_3$)?

Answer: H-P-H with one lone pair on P and an additional H. Trigonal pyramidal shape with phosphorus as central atom.

Flashcard 6: What does a triple bond indicate in a Lewis Diagram?

Answer: Three pairs of shared electrons. Triple bonds involve six electrons in three pairs.

Flashcard 7: How are lone pairs visually represented in Lewis Diagrams?

Answer: As pairs of dots around the atom. Dots show unshared electrons around atomic symbols.

Flashcard 8: State the Lewis Diagram for hydrogen chloride ($HCl$).

Answer: H-Cl with three lone pairs on Cl. Polar molecule with chlorine having three lone pairs.

Flashcard 9: What is the purpose of a Lewis Diagram?

Answer: To show the bonding between atoms and lone pairs of electrons. Visualizes electron distribution and chemical bonding patterns.

Flashcard 10: How do you denote resonance in Lewis Diagrams?

Answer: By using double-headed arrows between structures. Shows electron delocalization across multiple structures.

Flashcard 11: What symbol is used for a lone pair of electrons in Lewis Diagrams?

Answer: Dots around the atom. Two dots represent an unshared electron pair.

Flashcard 12: How are expanded octets represented in Lewis Diagrams?

Answer: With more than eight electrons around the central atom. Shows atoms with more than 8 valence electrons.

Flashcard 13: How many lone pairs are on the nitrogen in ammonia's Lewis Diagram?

Answer: One lone pair. Nitrogen uses three electrons for bonds, two remain as lone pair.

Flashcard 14: State the Lewis Diagram for dichloromethane ($CH_2Cl_2$).

Answer: H-C-Cl with an additional H and Cl bonded to C. Tetrahedral carbon with two hydrogen and two chlorine atoms.

Flashcard 15: What does a triple bond indicate in a Lewis Diagram?

Answer: Three pairs of shared electrons. Triple bonds involve six electrons in three pairs.

Flashcard 16: How are lone pairs visually represented in Lewis Diagrams?

Answer: As pairs of dots around the atom. Dots show unshared electrons around atomic symbols.

Flashcard 17: Which element can exceed the octet rule in Lewis Diagrams?

Answer: Phosphorus. Third period elements can use d orbitals for bonding.

Flashcard 18: How do you denote resonance in Lewis Diagrams?

Answer: By using double-headed arrows between structures. Shows electron delocalization across multiple structures.

Flashcard 19: What is the Lewis Diagram for nitric oxide ($NO$)?

Answer: N=O with one lone pair on N and two on O. Radical molecule with unpaired electron on nitrogen.

Flashcard 20: Identify the Lewis Diagram for ozone ($O_3$).

Answer: O=O-O with one lone pair on the central O and two on the others. Bent molecule showing resonance between oxygen atoms.

Flashcard 21: How do you denote resonance in Lewis Diagrams?

Answer: By using double-headed arrows between structures. Shows electron delocalization across multiple structures.

Flashcard 22: Find the error in this Lewis Diagram for water: H-O-H

Answer: Missing two lone pairs on the oxygen. Oxygen needs two lone pairs to complete its octet.

Flashcard 23: How do you represent a single bond in a Lewis Diagram?

Answer: With a single line between two atoms. One line equals one electron pair shared between atoms.

Flashcard 24: How many lone pairs are on the nitrogen in ammonia's Lewis Diagram?

Answer: One lone pair. Nitrogen uses three electrons for bonds, two remain as lone pair.

Flashcard 25: What is the Lewis Diagram for a nitrogen molecule ($N_2$)?

Answer: N≡N. Triple bond forms when nitrogen atoms share three electron pairs.

Flashcard 26: Which element is represented by the symbol 'Cl' in a Lewis Diagram?

Answer: Chlorine. Cl is the chemical symbol for this halogen element.

Flashcard 27: What is the purpose of a Lewis Diagram?

Answer: To show the bonding between atoms and lone pairs of electrons. Visualizes electron distribution and chemical bonding patterns.

Flashcard 28: What does a triple bond indicate in a Lewis Diagram?

Answer: Three pairs of shared electrons. Triple bonds involve six electrons in three pairs.

Flashcard 29: Identify the Lewis Diagram for boron trifluoride ($BF_3$).

Answer: F-B-F with one additional F atom bonded to B. Trigonal planar with boron having incomplete octet.

Flashcard 30: What symbol is used for a lone pair of electrons in Lewis Diagrams?

Answer: Dots around the atom. Two dots represent an unshared electron pair.

Flashcard 31: Identify the Lewis Diagram for a diatomic oxygen molecule.

Answer: :O::O: or O=O. Double bond between oxygens with two lone pairs each.

Flashcard 32: What is the Lewis Diagram for a nitrogen molecule ($N_2$)?

Answer: N≡N. Triple bond forms when nitrogen atoms share three electron pairs.

Flashcard 33: Identify the Lewis Diagram for a diatomic oxygen molecule.

Answer: :O::O: or O=O. Double bond between oxygens with two lone pairs each.

Flashcard 34: State the Lewis Diagram for acetylene ($C_2H_2$).

Answer: H-C≡C-H. Linear molecule with carbon-carbon triple bond.

Flashcard 35: How many covalent bonds does nitrogen typically form?

Answer: Three covalent bonds. Uses three of its five valence electrons for bonding.

Flashcard 36: What is the Lewis Diagram for formaldehyde ($CH_2O$)?

Answer: H-C=O with an additional H on C and two lone pairs on O. Planar molecule with carbon-oxygen double bond.

Flashcard 37: What is the Lewis Diagram for hydrogen peroxide ($H_2O_2$)?

Answer: H-O-O-H with two lone pairs on each O. Chain structure with oxygen-oxygen single bond.

Flashcard 38: State the Lewis Diagram for hydrogen chloride ($HCl$).

Answer: H-Cl with three lone pairs on Cl. Polar molecule with chlorine having three lone pairs.

Flashcard 39: What is the Lewis Diagram for carbon dioxide ($CO_2$)?

Answer: O=C=O. Linear molecule with carbon forming two double bonds.

Flashcard 40: How do you represent a single bond in a Lewis Diagram?

Answer: With a single line between two atoms. One line equals one electron pair shared between atoms.

Flashcard 41: What is the typical valence electron count for nitrogen in Lewis Diagrams?

Answer: Five. Nitrogen is in group 15 of the periodic table.

Flashcard 42: Identify the Lewis Diagram for carbon tetrachloride ($CCl_4$).

Answer: Cl-C-Cl with two additional Cl atoms bonded to C. Tetrahedral structure with carbon bonded to four chlorines.

Flashcard 43: What is the Lewis Diagram for phosphine ($PH_3$)?

Answer: H-P-H with one lone pair on P and an additional H. Trigonal pyramidal shape with phosphorus as central atom.

Flashcard 44: How many lone pairs are on the oxygen in water's Lewis Diagram?

Answer: Two lone pairs. Oxygen has 6 valence electrons, forms 2 bonds, leaves 4 as lone pairs.

Flashcard 45: Identify the Lewis Diagram for sulfur dioxide ($SO_2$).

Answer: O=S-O with one lone pair on S and two on each O. Bent structure due to lone pair repulsion on sulfur.

Flashcard 46: Identify the Lewis Diagram for a diatomic oxygen molecule.

Answer: :O::O: or O=O. Double bond between oxygens with two lone pairs each.

Flashcard 47: What is the Lewis Diagram for ethylene ($C_2H_4$)?

Answer: H-C=C-H with additional H atoms bonded to each C. Planar molecule with carbon-carbon double bond.

Flashcard 48: What is the Lewis Diagram for sulfur hexafluoride ($SF_6$)?

Answer: F-S-F with four additional F atoms bonded to S. Octahedral structure utilizing sulfur's expanded octet.

Flashcard 49: Identify the Lewis Diagram for sulfur dioxide ($SO_2$).

Answer: O=S-O with one lone pair on S and two on each O. Bent structure due to lone pair repulsion on sulfur.

Flashcard 50: How are lone pairs visually represented in Lewis Diagrams?

Answer: As pairs of dots around the atom. Dots show unshared electrons around atomic symbols.

Flashcard 51: What is the significance of the octet rule in Lewis Diagrams?

Answer: Atoms tend to have eight electrons in their valence shell. Stable electron configuration for most main group elements.

Flashcard 52: State the Lewis Diagram for dichloromethane ($CH_2Cl_2$).

Answer: H-C-Cl with an additional H and Cl bonded to C. Tetrahedral carbon with two hydrogen and two chlorine atoms.

Flashcard 53: State the Lewis Diagram for methane ($CH_4$).

Answer: H-C-H with two additional H atoms bonded to C. Tetrahedral structure with carbon bonded to four hydrogens.

Flashcard 54: How many bonds are typically formed by oxygen in Lewis Diagrams?

Answer: Two bonds. Oxygen typically forms two covalent bonds to complete octet.

Flashcard 55: What is the purpose of a Lewis Diagram?

Answer: To show the bonding between atoms and lone pairs of electrons. Visualizes electron distribution and chemical bonding patterns.

Flashcard 56: What is the Lewis Diagram for phosphine ($PH_3$)?

Answer: H-P-H with one lone pair on P and an additional H. Trigonal pyramidal shape with phosphorus as central atom.

Flashcard 57: What is the significance of the octet rule in Lewis Diagrams?

Answer: Atoms tend to have eight electrons in their valence shell. Stable electron configuration for most main group elements.

Flashcard 58: How do you represent a shared electron pair in a Lewis Diagram?

Answer: With a line between the two atoms. Line notation represents covalent bonding electrons.

Flashcard 59: State the Lewis Diagram for methane ($CH_4$).

Answer: H-C-H with two additional H atoms bonded to C. Tetrahedral structure with carbon bonded to four hydrogens.

Flashcard 60: How many valence electrons does carbon have in a Lewis Diagram?

Answer: Four. Carbon is in group 14, giving it 4 valence electrons.

Flashcard 61: State the Lewis Diagram for acetylene ($C_2H_2$).

Answer: H-C≡C-H. Linear molecule with carbon-carbon triple bond.

Flashcard 62: State the Lewis Diagram for hydrogen chloride ($HCl$).

Answer: H-Cl with three lone pairs on Cl. Polar molecule with chlorine having three lone pairs.

Flashcard 63: What is the Lewis Diagram for carbon dioxide ($CO_2$)?

Answer: O=C=O. Linear molecule with carbon forming two double bonds.

Flashcard 64: How are double bonds represented in Lewis Diagrams?

Answer: With two parallel lines between the bonded atoms. Two parallel lines indicate four shared electrons.

Flashcard 65: What is the typical valence electron count for nitrogen in Lewis Diagrams?

Answer: Five. Nitrogen is in group 15 of the periodic table.

Flashcard 66: What is the Lewis Diagram for nitric oxide ($NO$)?

Answer: N=O with one lone pair on N and two on O. Radical molecule with unpaired electron on nitrogen.

Flashcard 67: How many covalent bonds does nitrogen typically form?

Answer: Three covalent bonds. Uses three of its five valence electrons for bonding.

Flashcard 68: What is the Lewis Diagram for nitric oxide ($NO$)?

Answer: N=O with one lone pair on N and two on O. Radical molecule with unpaired electron on nitrogen.

Flashcard 69: Identify the Lewis Diagram for ammonia ($NH_3$).

Answer: H-N-H with one lone pair on N and an additional H. Trigonal pyramidal with nitrogen forming three bonds.

Flashcard 70: What symbol is used for a lone pair of electrons in Lewis Diagrams?

Answer: Dots around the atom. Two dots represent an unshared electron pair.

Flashcard 71: How do you represent a shared electron pair in a Lewis Diagram?

Answer: With a line between the two atoms. Line notation represents covalent bonding electrons.

Flashcard 72: Which element is represented by the symbol 'Cl' in a Lewis Diagram?

Answer: Chlorine. Cl is the chemical symbol for this halogen element.

Flashcard 73: How many lone pairs are on the nitrogen in ammonia's Lewis Diagram?

Answer: One lone pair. Nitrogen uses three electrons for bonds, two remain as lone pair.

Flashcard 74: How do you represent a shared electron pair in a Lewis Diagram?

Answer: With a line between the two atoms. Line notation represents covalent bonding electrons.

Flashcard 75: Identify the Lewis Diagram for ammonia ($NH_3$).

Answer: H-N-H with one lone pair on N and an additional H. Trigonal pyramidal with nitrogen forming three bonds.

Flashcard 76: What is the Lewis Diagram for formaldehyde ($CH_2O$)?

Answer: H-C=O with an additional H on C and two lone pairs on O. Planar molecule with carbon-oxygen double bond.

Flashcard 77: What does each line in a Lewis Diagram represent?

Answer: A pair of shared electrons. Each line shows a covalent bond of two electrons.

Flashcard 78: What is the Lewis Diagram for carbon dioxide ($CO_2$)?

Answer: O=C=O. Linear molecule with carbon forming two double bonds.

Flashcard 79: What symbol is used for a lone pair of electrons in Lewis Diagrams?

Answer: Dots around the atom. Two dots represent an unshared electron pair.

Flashcard 80: Identify the Lewis Diagram for ammonia ($NH_3$).

Answer: H-N-H with one lone pair on N and an additional H. Trigonal pyramidal with nitrogen forming three bonds.

Flashcard 81: How many lone pairs are on the nitrogen in ammonia's Lewis Diagram?

Answer: One lone pair. Nitrogen uses three electrons for bonds, two remain as lone pair.

Flashcard 82: Identify the Lewis Diagram for ozone ($O_3$).

Answer: O=O-O with one lone pair on the central O and two on the others. Bent molecule showing resonance between oxygen atoms.

Flashcard 83: How many bonds are typically formed by oxygen in Lewis Diagrams?

Answer: Two bonds. Oxygen typically forms two covalent bonds to complete octet.

Flashcard 84: How do you represent a single bond in a Lewis Diagram?

Answer: With a single line between two atoms. One line equals one electron pair shared between atoms.

Flashcard 85: How many bonds are typically formed by oxygen in Lewis Diagrams?

Answer: Two bonds. Oxygen typically forms two covalent bonds to complete octet.

Flashcard 86: How many bonds are typically formed by oxygen in Lewis Diagrams?

Answer: Two bonds. Oxygen typically forms two covalent bonds to complete octet.

Flashcard 87: State the Lewis Diagram for methane ($CH_4$).

Answer: H-C-H with two additional H atoms bonded to C. Tetrahedral structure with carbon bonded to four hydrogens.

Flashcard 88: Identify the Lewis Diagram for boron trifluoride ($BF_3$).

Answer: F-B-F with one additional F atom bonded to B. Trigonal planar with boron having incomplete octet.

Flashcard 89: State the Lewis Diagram for acetylene ($C_2H_2$).

Answer: H-C≡C-H. Linear molecule with carbon-carbon triple bond.

Flashcard 90: What is the Lewis Diagram for hydrogen peroxide ($H_2O_2$)?

Answer: H-O-O-H with two lone pairs on each O. Chain structure with oxygen-oxygen single bond.

Flashcard 91: How many covalent bonds does nitrogen typically form?

Answer: Three covalent bonds. Uses three of its five valence electrons for bonding.

Flashcard 92: What is the Lewis Diagram for ethylene ($C_2H_4$)?

Answer: H-C=C-H with additional H atoms bonded to each C. Planar molecule with carbon-carbon double bond.

Flashcard 93: What is the Lewis Diagram for hydrogen peroxide ($H_2O_2$)?

Answer: H-O-O-H with two lone pairs on each O. Chain structure with oxygen-oxygen single bond.

Flashcard 94: What is the Lewis Diagram for phosphine ($PH_3$)?

Answer: H-P-H with one lone pair on P and an additional H. Trigonal pyramidal shape with phosphorus as central atom.

Flashcard 95: Which element can exceed the octet rule in Lewis Diagrams?

Answer: Phosphorus. Third period elements can use d orbitals for bonding.

Flashcard 96: How do you denote resonance in Lewis Diagrams?

Answer: By using double-headed arrows between structures. Shows electron delocalization across multiple structures.

Flashcard 97: What is the Lewis Diagram for carbon dioxide ($CO_2$)?

Answer: O=C=O. Linear molecule with carbon forming two double bonds.

Flashcard 98: Which element can exceed the octet rule in Lewis Diagrams?

Answer: Phosphorus. Third period elements can use d orbitals for bonding.

Flashcard 99: What is the Lewis Diagram for ethylene ($C_2H_4$)?

Answer: H-C=C-H with additional H atoms bonded to each C. Planar molecule with carbon-carbon double bond.

Flashcard 100: What is the Lewis Diagram for a nitrogen molecule ($N_2$)?

Answer: N≡N. Triple bond forms when nitrogen atoms share three electron pairs.