Podcast
Questions and Answers
A structural formula shows the arrangement of the atoms in a molecule.
A structural formula shows the arrangement of the atoms in a molecule.
True (A)
The central atom in a molecule is the one with the highest electron affinity.
The central atom in a molecule is the one with the highest electron affinity.
False (B)
In molecules, hydrogen is always a terminal atom.
In molecules, hydrogen is always a terminal atom.
True (A)
The number of bonding pairs in a molecule is equal to the number of electrons.
The number of bonding pairs in a molecule is equal to the number of electrons.
To find the total number of electrons available for bonding in a positive ion, you should add the ion charge to the total number of valence electrons of the atoms present.
To find the total number of electrons available for bonding in a positive ion, you should add the ion charge to the total number of valence electrons of the atoms present.
The electrons in a coordinate covalent bond are donated by both bonded atoms.
The electrons in a coordinate covalent bond are donated by both bonded atoms.
Resonance occurs when more than one valid Lewis structure can be written for a molecule.
Resonance occurs when more than one valid Lewis structure can be written for a molecule.
Nitrate is an example of an ion that forms resonance structures.
Nitrate is an example of an ion that forms resonance structures.
The carbon dioxide molecule contains two double bonds.
The carbon dioxide molecule contains two double bonds.
All electrons in an atom are available for bonding.
All electrons in an atom are available for bonding.
In the sulfate ion (SO4 2-), 32 electrons are available for bonding.
In the sulfate ion (SO4 2-), 32 electrons are available for bonding.
When carbon and oxygen bond, the molecule contains ten pairs of bonding electrons.
When carbon and oxygen bond, the molecule contains ten pairs of bonding electrons.
Identify the molecule with an odd number of valence electrons.
Identify the molecule with an odd number of valence electrons.
Identify the molecule with fewer than 8 electrons around an atom.
Identify the molecule with fewer than 8 electrons around an atom.
Identify the molecule with more than 8 electrons around the central atom.
Identify the molecule with more than 8 electrons around the central atom.
Identify the molecule that has more than one valid Lewis structure.
Identify the molecule that has more than one valid Lewis structure.
The VSEPR model is used mainly to determine what?
The VSEPR model is used mainly to determine what?
What is the bond angle?
What is the bond angle?
What is the basis of the VSEPR model?
What is the basis of the VSEPR model?
What is the shape of a molecule whose central atom has four pairs of bonding electrons?
What is the shape of a molecule whose central atom has four pairs of bonding electrons?
What is the shape of a molecule that has two covalent single bonds and no lone pairs on the central atom?
What is the shape of a molecule that has two covalent single bonds and no lone pairs on the central atom?
What is the shape of a molecule that has three single covalent bonds and one lone pair on the central atom?
What is the shape of a molecule that has three single covalent bonds and one lone pair on the central atom?
The formation of new orbitals from a combination or rearrangement of valence electrons is called __.
The formation of new orbitals from a combination or rearrangement of valence electrons is called __.
The orbitals that are produced through hybridization are __ to one another.
The orbitals that are produced through hybridization are __ to one another.
An example of an element that commonly undergoes hybridization is __.
An example of an element that commonly undergoes hybridization is __.
When carbon combines three p orbitals and its one s orbital, the orbitals that result are called __.
When carbon combines three p orbitals and its one s orbital, the orbitals that result are called __.
An example of a molecule that has sp3 is __.
An example of a molecule that has sp3 is __.
What is the meaning of the term electronegativity?
What is the meaning of the term electronegativity?
Which element has the highest electronegativity? What is the numerical value? What are the name and group number of the chemical family that has the highest overall electronegativities?
Which element has the highest electronegativity? What is the numerical value? What are the name and group number of the chemical family that has the highest overall electronegativities?
Which element has the lowest electronegativity? What is the numerical value? What are the name and group number of the chemical family that has the lowest overall electronegativities?
Which element has the lowest electronegativity? What is the numerical value? What are the name and group number of the chemical family that has the lowest overall electronegativities?
What general trend in electronegativity do you note going down a group? Across a period?
What general trend in electronegativity do you note going down a group? Across a period?
How are the electronegativity values used to determine the type of bond that exists between two atoms?
How are the electronegativity values used to determine the type of bond that exists between two atoms?
Ionic compounds are usually soluble in polar substances.
Ionic compounds are usually soluble in polar substances.
In a covalent molecular compound, the attraction between molecules tends to be strong.
In a covalent molecular compound, the attraction between molecules tends to be strong.
Unequal sharing of electrons between two bonded atoms always indicates what?
Unequal sharing of electrons between two bonded atoms always indicates what?
When electronegativities of two bonded atoms differ greatly, the bond is what?
When electronegativities of two bonded atoms differ greatly, the bond is what?
What is the electronegativity difference that usually is the dividing line between covalent and ionic bonds?
What is the electronegativity difference that usually is the dividing line between covalent and ionic bonds?
The symbol delta is placed next to what?
The symbol delta is placed next to what?
A nonpolar covalent bond is one in which?
A nonpolar covalent bond is one in which?
Molecules containing only polar covalent bonds?
Molecules containing only polar covalent bonds?
What factor other than electronegativity determines whether a molecule as a whole is polar or not?
What factor other than electronegativity determines whether a molecule as a whole is polar or not?
What correctly describes the compound water H2O?
What correctly describes the compound water H2O?
What correctly describes the compound carbon tetrachloride, CCl4?
What correctly describes the compound carbon tetrachloride, CCl4?
A molecule of ammonia, NH3, is?
A molecule of ammonia, NH3, is?
Study Notes
Structural Formulas and Bonding
- A structural formula illustrates the arrangement of atoms within a molecule.
- In a molecule, hydrogen atoms are always positioned as terminal atoms.
- The number of bonding pairs does not equal the total number of electrons in a molecule.
- The electrons in a coordinate covalent bond are only donated by one atom, not both.
Resonance and Molecular Structures
- Resonance occurs when multiple valid Lewis structures can be created for a single molecule.
- Nitrate (NO3-) is an example of an ion that can have resonance structures.
- Carbon dioxide (CO2) contains two double bonds, contributing to its linear structure.
Bonding Electrons and Ions
- In the sulfate ion (SO4 2-), a total of 32 electrons are available for bonding.
- Electrons in an atom are not all available for bonding due to filled electron shells.
Molecular Geometry and VSEPR Theory
- The VSEPR model is utilized to determine the shapes of molecules based on electron pair repulsion.
- Bond angles are measured between two terminal atoms and the central atom within a molecule.
- Molecules can exhibit various shapes:
- Tetrahedral shape occurs with four pairs of bonding electrons.
- Linear shape is formed with two covalent single bonds without lone pairs.
- Trigonal pyramidal shape has three single covalent bonds and one lone pair.
Hybridization
- Hybridization refers to the formation of new orbitals from combined valence electrons.
- Hybrid orbitals generated are identical to one another, such as in carbon.
- Carbon commonly undergoes hybridization, forming sp3 orbitals when combining three p orbitals with one s orbital.
- Methane (CH4) is an example of a molecule displaying sp3 hybridization.
Electronegativity
- Electronegativity measures an atom's ability to attract electrons in a bond.
- Fluorine holds the highest electronegativity value at 3.98 among all elements, classified under halogens in group 7A.
- Francium has the lowest electronegativity at 0.7, belonging to alkali metals in group 1A.
- Electronegativity decreases down a group and increases across a period.
Bond Types and Properties
- The difference in electronegativities indicates bond type: a difference of 1.7 or more typically indicates an ionic bond.
- Polar covalent bonds result from unequal electron sharing between bonded atoms.
- A nonpolar covalent bond involves equal electron sharing between atoms.
- The delta symbol (δ) indicates the less electronegative atom in a polar covalent bond.
Molecular Polarity
- Molecules with only polar covalent bonds may or may not exhibit overall polarity based on their geometric arrangement.
- Water (H2O) is considered a polar molecule with polar covalent bonds and unique geometry (bent).
- Carbon tetrachloride (CCl4) is nonpolar overall, despite containing polar covalent bonds.
- Ammonia (NH3) is polar because significant electronegativity differences result in a trigonal pyramidal shape.
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Test your understanding of key concepts from Chemistry Chapter 9 with these flashcards. Each card explores important definitions and statements regarding molecular structures and bonding. Perfect for quick review and reinforcement of your chemistry knowledge!
