Podcast
Questions and Answers
Which scientist developed a model that can be used to predict the structure of a molecule?
Which scientist developed a model that can be used to predict the structure of a molecule?
- Joseph Proust
- John Dalton
- Ernest Rutherford
- G.N.Lewis (correct)
Which atom has a Lewis structure with an octet?
Which atom has a Lewis structure with an octet?
- Cl
- Na
- Mg
- Ar (correct)
In a Lewis structure, a dash drawn between two atoms represents _______________.
In a Lewis structure, a dash drawn between two atoms represents _______________.
a shared electron pair
Which of the following atoms would most likely be terminal in a Lewis structure?
Which of the following atoms would most likely be terminal in a Lewis structure?
Which of the following descriptions best describes the type of electrons used to write a Lewis structure?
Which of the following descriptions best describes the type of electrons used to write a Lewis structure?
Which of the following is an exception to the octet rule?
Which of the following is an exception to the octet rule?
Which of the following symbols are used to illustrate commonalities between two or more resonance structures?
Which of the following symbols are used to illustrate commonalities between two or more resonance structures?
How many resonance structures exist for the formate ion, HCO2−?
How many resonance structures exist for the formate ion, HCO2−?
Which of these molecules or ions exhibit resonance?
Which of these molecules or ions exhibit resonance?
Construct an orbital diagram to show the electron configuration for a neutral magnesium atom, Mg.
Construct an orbital diagram to show the electron configuration for a neutral magnesium atom, Mg.
To form a stable ion, will magnesium gain or lose electrons? How many electrons?
To form a stable ion, will magnesium gain or lose electrons? How many electrons?
Match each ion with the noble gas whose electron configuration it shares.
Match each ion with the noble gas whose electron configuration it shares.
How many electrons are transferred between the cation and anion to form the ionic bond in one formula unit of each compound?
How many electrons are transferred between the cation and anion to form the ionic bond in one formula unit of each compound?
Which nonmetals could form an ionic compound with magnesium with the formula MgX2 (where X represents the nonmetal)?
Which nonmetals could form an ionic compound with magnesium with the formula MgX2 (where X represents the nonmetal)?
Use Lewis theory to determine the formula for the compound that forms from Al and S.
Use Lewis theory to determine the formula for the compound that forms from Al and S.
Use Lewis theory to determine the formula for the compound that forms from Na and S.
Use Lewis theory to determine the formula for the compound that forms from Na and S.
Use Lewis theory to determine the formula for the compound that forms from Sr and Se.
Use Lewis theory to determine the formula for the compound that forms from Sr and Se.
Use Lewis theory to determine the formula for the compound that forms from Ba and F.
Use Lewis theory to determine the formula for the compound that forms from Ba and F.
Use the Lewis model to predict the correct formula for the compound that forms between Ca and Br.
Use the Lewis model to predict the correct formula for the compound that forms between Ca and Br.
How many total valence electrons are in the Lewis structure of NO3−?
How many total valence electrons are in the Lewis structure of NO3−?
Determine the electron geometry of N2O (oxygen is terminal).
Determine the electron geometry of N2O (oxygen is terminal).
Determine the molecular geometry of N2O (oxygen is terminal).
Determine the molecular geometry of N2O (oxygen is terminal).
Determine the electron geometry of SO2.
Determine the electron geometry of SO2.
Determine the molecular geometry of SO2.
Determine the molecular geometry of SO2.
Determine the electron geometry of H2S.
Determine the electron geometry of H2S.
Determine the molecular geometry of H2S.
Determine the molecular geometry of H2S.
Determine the electron geometry of PF3.
Determine the electron geometry of PF3.
Determine the molecular geometry of PF3.
Determine the molecular geometry of PF3.
CO2−3
CO2−3
ClO−2
ClO−2
NO−3
NO−3
NH+4
NH+4
What is the molecular geometry of N2O (Nitrogen is the central atom)?
What is the molecular geometry of N2O (Nitrogen is the central atom)?
What is the molecular geometry of PBr3?
What is the molecular geometry of PBr3?
Which bond is polar?
Which bond is polar?
Which molecule is polar?
Which molecule is polar?
If a molecule has polar bonds, is the molecule itself polar?
If a molecule has polar bonds, is the molecule itself polar?
Why?
Why?
How do you determine the number of electrons that go into the Lewis structure of a molecule?
How do you determine the number of electrons that go into the Lewis structure of a molecule?
What happens if you try to mix a polar liquid with a nonpolar one?
What happens if you try to mix a polar liquid with a nonpolar one?
Use the Lewis model to explain why the compound that forms between hydrogen and sulfur has the formula H2S.
Use the Lewis model to explain why the compound that forms between hydrogen and sulfur has the formula H2S.
Would you expect HS to be stable?
Would you expect HS to be stable?
Would you expect H3S to be stable?
Would you expect H3S to be stable?
If all of the electron groups around a central atom are bonding groups (that is, there are no lone pairs), what is the molecular geometry for two electron groups?
If all of the electron groups around a central atom are bonding groups (that is, there are no lone pairs), what is the molecular geometry for two electron groups?
If all of the electron groups around a central atom are bonding groups (that is, there are no lone pairs), what is the molecular geometry for three electron groups?
If all of the electron groups around a central atom are bonding groups (that is, there are no lone pairs), what is the molecular geometry for three electron groups?
If all of the electron groups around a central atom are bonding groups (that is, there are no lone pairs), what is the molecular geometry for four electron groups?
If all of the electron groups around a central atom are bonding groups (that is, there are no lone pairs), what is the molecular geometry for four electron groups?
Indicate which of the electrons in the electron configuration are shown in the Lewis structure.
Indicate which of the electrons in the electron configuration are shown in the Lewis structure.
Indicate which of the electrons in the electron configuration are shown in the Lewis structure.
Indicate which of the electrons in the electron configuration are shown in the Lewis structure.
Electron groups: 2. Bonding groups: 2. Lone pairs: 0.
Electron groups: 2. Bonding groups: 2. Lone pairs: 0.
Bonding groups: 3. Lone pairs: 0.
Bonding groups: 3. Lone pairs: 0.
Bonding groups: 2. Lone pairs: 1.
Bonding groups: 2. Lone pairs: 1.
Bonding groups: 4. Lone pairs: 0.
Bonding groups: 4. Lone pairs: 0.
Bonding groups: 3. Lone pairs: 1.
Bonding groups: 3. Lone pairs: 1.
Bonding groups: 2. Lone pairs: 2.
Bonding groups: 2. Lone pairs: 2.
How many bonding electrons are in the Lewis structure of N2?
How many bonding electrons are in the Lewis structure of N2?
How many bonding electrons are in the Lewis structure of carbon monoxide, CO?
How many bonding electrons are in the Lewis structure of carbon monoxide, CO?
How many valence electrons are in the nitrate ion?
How many valence electrons are in the nitrate ion?
The correct Lewis structure for BF3 would be exactly:
The correct Lewis structure for BF3 would be exactly:
Which of the following compounds have resonance structures?
Which of the following compounds have resonance structures?
The VSEPR theory predicts that the angle between the central carbon atom and the two oxygen atoms in CO2 measures 180°.
The VSEPR theory predicts that the angle between the central carbon atom and the two oxygen atoms in CO2 measures 180°.
What is the angle between electron groups in the linear electron geometry?
What is the angle between electron groups in the linear electron geometry?
When you have 4 electron groups and none of them are lone pairs, the molecular geometry is trigonal pyramidal.
When you have 4 electron groups and none of them are lone pairs, the molecular geometry is trigonal pyramidal.
What is the molecular geometry if you have 4 single bonds around the central atom?
What is the molecular geometry if you have 4 single bonds around the central atom?
What is the electron geometry if you have 3 electron groups around the center atom?
What is the electron geometry if you have 3 electron groups around the center atom?
What is the molecular geometry of CCl4?
What is the molecular geometry of CCl4?
The electron geometry and the molecular geometry of ammonia (NH3) are, respectively:
The electron geometry and the molecular geometry of ammonia (NH3) are, respectively:
The elements with the highest electronegativity values tend to be found in the:
The elements with the highest electronegativity values tend to be found in the:
Which molecule listed below has a polar covalent bond?
Which molecule listed below has a polar covalent bond?
Which molecule listed below has a nonpolar covalent bond?
Which molecule listed below has a nonpolar covalent bond?
Which molecule listed below is a polar molecule?
Which molecule listed below is a polar molecule?
Which of the following statements are TRUE about the BF3 molecule?
Which of the following statements are TRUE about the BF3 molecule?
Consider the following electronegativity values: H = 2.1, Cl = 3.0, F = 4.0. Which molecule below would you expect to have the more polar bond?
Consider the following electronegativity values: H = 2.1, Cl = 3.0, F = 4.0. Which molecule below would you expect to have the more polar bond?
The electronegativity value for Mg is 1.2 and the value for O is 3.5. Based on these values, what type of bond is expected for a compound formed between Mg and O?
The electronegativity value for Mg is 1.2 and the value for O is 3.5. Based on these values, what type of bond is expected for a compound formed between Mg and O?
Electronegativity Difference
Electronegativity Difference
CBr4
CBr4
H2CO
H2CO
CS2
CS2
BH3
BH3
Study Notes
G.N. Lewis and Lewis Structures
- G.N. Lewis developed a model for predicting molecular structures.
- Lewis structures use symbols to represent atoms, with dots for valence electrons.
- A dash between atoms indicates a shared electron pair.
Valence Electrons and Octet Rule
- Valence electrons are the electrons involved in chemical bonding.
- Noble gases typically have a complete octet, contributing to their stability (e.g., Ar has an octet).
- Exceptions to the octet rule include molecules like SF6.
Resonance Structures
- Resonance occurs when more than one valid Lewis structure can be drawn for a molecule.
- The symbol ↔ illustrates shared characteristics between multiple resonance structures.
- The formate ion (HCO2−) has 2 resonance structures.
Electron and Molecular Geometry
- Electron geometry considers bonding and lone pairs around a central atom.
- For two electron groups: linear geometry (180° angle).
- For three electron groups: trigonal planar geometry (120° angle).
- For four electron groups: tetrahedral geometry (109.5° angle).
Bonding and Ions
- Ionic compounds form from the transfer of electrons between metals and nonmetals.
- Magnesium typically loses two electrons to form a stable ion.
- Common ionic compounds include Na2S and BaF2.
- Elements with high electronegativity often form polar bonds, as seen in H2O and HF.
Polar vs. Nonpolar Molecules
- Polar molecules have an uneven distribution of charge due to their molecular structure and bonds.
- Nonpolar molecules, like H2, have an even charge distribution.
- Geometry plays a crucial role in determining whether a molecule is polar or nonpolar.
Molecular Shapes
- Molecular geometry determines physical properties and reactivity.
- Examples of molecular geometries include:
- NH3: Trigonal pyramidal
- H2S: Bent
- CO2: Linear
- CF4: Tetrahedral
Electronegativity and Bonding Types
- Electronegativity differences determine bond types:
- Pure covalent (0-0.4), polar covalent (0.4-2.0), and ionic (2.0+).
- Compounds formed from Mg and O are expected to be ionic due to their significant electronegativity difference.
Summary of Notable Compounds
- Ozone (O3) exhibits resonance structures.
- BF3 is nonpolar with trigonal planar geometry and violates the octet rule.
- The molecule HCN and others like NH3 and H2O are polar due to their structure and electronegativity differences.
Important Concepts in Lewis Structures
- When counting electrons for Lewis structures, sum the valence electrons from all atoms involved.
- Mixing polar and nonpolar liquids results in separation into distinct regions rather than forming a homogenous solution.
- Stable compounds can form despite differing electron configurations, emphasizing understanding of valence electrons and molecular geometries.
VSEPR Theory
- VSEPR (Valence Shell Electron Pair Repulsion) theory predicts molecular shapes based on repulsion between electron groups.
- Molecules with no lone pairs around a central atom exhibit clear geometric arrangements (linear, trigonal planar, tetrahedral).
Studying That Suits You
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Test your knowledge on Lewis structures and molecular predictions with these flashcards from Chemistry Chapter 10. Each card will challenge you with questions about notable scientists and atomic structures. Perfect for revision and reinforcing your understanding.
