Questions and Answers
A structural formula shows the arrangement of the atoms in a molecule.
True
The central atom in a molecule is the one with the highest electron affinity.
False
In molecules, hydrogen is always a terminal atom.
True
The number of bonding pairs in a molecule is equal to the number of electrons.
Signup and view all the answers
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.
Signup and view all the answers
The electrons in a coordinate covalent bond are donated by both bonded atoms.
Signup and view all the answers
Resonance occurs when more than one valid Lewis structure can be written for a molecule.
Signup and view all the answers
Nitrate is an example of an ion that forms resonance structures.
Signup and view all the answers
The carbon dioxide molecule contains two double bonds.
Signup and view all the answers
All electrons in an atom are available for bonding.
Signup and view all the answers
In the sulfate ion (SO4 2-), 32 electrons are available for bonding.
Signup and view all the answers
When carbon and oxygen bond, the molecule contains ten pairs of bonding electrons.
Signup and view all the answers
Identify the molecule with an odd number of valence electrons.
Signup and view all the answers
Identify the molecule with fewer than 8 electrons around an atom.
Signup and view all the answers
Identify the molecule with more than 8 electrons around the central atom.
Signup and view all the answers
Identify the molecule that has more than one valid Lewis structure.
Signup and view all the answers
The VSEPR model is used mainly to determine what?
Signup and view all the answers
What is the bond angle?
Signup and view all the answers
What is the basis of the VSEPR model?
Signup and view all the answers
What is the shape of a molecule whose central atom has four pairs of bonding electrons?
Signup and view all the answers
What is the shape of a molecule that has two covalent single bonds and no lone pairs on the central atom?
Signup and view all the answers
What is the shape of a molecule that has three single covalent bonds and one lone pair on the central atom?
Signup and view all the answers
The formation of new orbitals from a combination or rearrangement of valence electrons is called __.
Signup and view all the answers
The orbitals that are produced through hybridization are __ to one another.
Signup and view all the answers
An example of an element that commonly undergoes hybridization is __.
Signup and view all the answers
When carbon combines three p orbitals and its one s orbital, the orbitals that result are called __.
Signup and view all the answers
An example of a molecule that has sp3 is __.
Signup and view all the answers
What is the meaning of the term electronegativity?
Signup and view all the answers
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?
Signup and view all the answers
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?
Signup and view all the answers
What general trend in electronegativity do you note going down a group? Across a period?
Signup and view all the answers
How are the electronegativity values used to determine the type of bond that exists between two atoms?
Signup and view all the answers
Ionic compounds are usually soluble in polar substances.
Signup and view all the answers
In a covalent molecular compound, the attraction between molecules tends to be strong.
Signup and view all the answers
Unequal sharing of electrons between two bonded atoms always indicates what?
Signup and view all the answers
When electronegativities of two bonded atoms differ greatly, the bond is what?
Signup and view all the answers
What is the electronegativity difference that usually is the dividing line between covalent and ionic bonds?
Signup and view all the answers
The symbol delta is placed next to what?
Signup and view all the answers
A nonpolar covalent bond is one in which?
Signup and view all the answers
Molecules containing only polar covalent bonds?
Signup and view all the answers
What factor other than electronegativity determines whether a molecule as a whole is polar or not?
Signup and view all the answers
What correctly describes the compound water H2O?
Signup and view all the answers
What correctly describes the compound carbon tetrachloride, CCl4?
Signup and view all the answers
A molecule of ammonia, NH3, is?
Signup and view all the answers
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.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
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!