Honors Chem Bonding Test
Flashcard 1
Q: What is VSEPR theory?
A: Valence Shell Electron Pair Repulsion theory states that electron pairs around a central atom will arrange themselves to minimize repulsion.
Flashcard 2
Q: How do lone pairs affect molecular shape?
A: Lone pairs occupy more space than bonding pairs, causing bond angles to be smaller and affecting the molecular geometry.
Flashcard 3
Q: What is the shape of a molecule with AX₂?
A: Linear, with a bond angle of 180°.
Flashcard 4
Q: What is the molecular shape of a molecule with AX₃?
A: Trigonal planar, with bond angles of 120°.
Flashcard 5
Q: What shape does a molecule with AX₄ have?
A: Tetrahedral, with bond angles of 109.5°.
Flashcard 6
Q: How does the presence of lone pairs affect the shape of a molecule?
A: Lone pairs reduce the bond angles between bonding pairs, often creating bent or angular shapes, such as in H₂O (AX₂E₂).
Flashcard 7
Q: What are polar covalent bonds?
A: Bonds where electrons are shared unequally due to differences in electronegativity, resulting in partial positive and negative charges.
Flashcard 8
Q: What is a dipole moment?
A: A measure of the separation of positive and negative charges in a molecule, indicating polarity.
Flashcard 9
Q: What is the difference between polar and nonpolar molecules?
A: Polar molecules have an asymmetrical charge distribution, while nonpolar molecules have a symmetrical charge distribution.
Flashcard 10
Q: How can you tell if a molecule is polar?
A: If the molecule has an uneven distribution of charge (asymmetrical) or contains polar bonds that do not cancel each other out, it is polar.
Flashcard 11
Q: What is a common example of a polar molecule?
A: Water (H₂O), with an AX₂E₂ shape, is polar because of its bent shape and the difference in electronegativity between hydrogen and oxygen.
Flashcard 12
Q: What is a nonpolar molecule example?
A: Carbon dioxide (CO₂), with an AX₂ shape, is nonpolar because it has a linear shape, and the dipoles of the C=O bonds cancel out.
Flashcard 13
Q: What is the relationship between polarity and solubility?
A: Polar molecules dissolve well in polar solvents (e.g., water), while nonpolar molecules dissolve in nonpolar solvents.
Flashcard 14
Q: What are London Dispersion Forces?
A: Weak intermolecular forces that occur due to temporary dipoles caused by uneven electron distribution in molecules.
Flashcard 15
Q: What factors influence the strength of London Dispersion Forces?
A: Molecular size (larger molecules with more electrons have stronger LDFs) and surface area.
Flashcard 16
Q: What is the primary intermolecular force in nonpolar molecules?
A: London Dispersion Forces (LDFs).
Flashcard 17
Q: What are dipole-dipole forces?
A: Intermolecular forces between polar molecules where the positive end of one molecule is attracted to the negative end of another.
Flashcard 18
Q: What is hydrogen bonding?
A: A strong dipole-dipole attraction that occurs when hydrogen is bonded to highly electronegative atoms like N, O, or F.
Flashcard 19
Q: Why does water have a strong dipole moment?
A: Water has a bent shape (AX₂E₂) with a large electronegativity difference between oxygen and hydrogen, creating a strong dipole moment with the oxygen end being negative and the hydrogen ends positive.
Flashcard 20
Q: What is a unit cell in a crystal lattice?
A: The smallest repeating pattern of a crystal structure.
Flashcard 21
Q: Why are ionic compounds like CsCl brittle?
A: Shifting layers of ions cause like charges to align and repel, breaking the crystal.
Flashcard 22
Q: What is the shape of a molecule with AX₂E?
A: Bent, with bond angles less than 120° due to the lone pair.
Flashcard 23
Q: What is the shape of a molecule with AX₃E?
A: Trigonal pyramidal, with bond angles less than 109.5° due to the lone pair.
Flashcard 24
Q: What is the shape of a molecule with AX₄E₂?
A: Octahedral, with bond angles of 90° and 180°, adjusted for the lone pairs.
Flashcard 25
Q: What is an example of a molecule with AX₃E₂?
A: An example is a T-shaped molecular geometry, such as chlorine trifluoride (ClF₃).
Flashcard 26
Q: What are dipole-dipole forces?
A: Intermolecular forces occurring between polar molecules, where the positive end of one molecule is attracted to the negative end of another.
Flashcard 27
Q: How do London Dispersion Forces (LDFs) arise?
A: They occur due to temporary dipoles caused by momentary uneven electron distribution in molecules.
Flashcard 28
Q: What factors increase the strength of London Dispersion Forces?
A: Larger molecular size (more electrons) and increased molecular surface area.
Flashcard 29
Q: Define hydrogen bonding and give an example.
A: A strong dipole-dipole attraction where hydrogen is bonded to highly electronegative atoms (N, O, or F). Example: H₂O.
Flashcard 30
Q: What is a polar molecule example with AX₃?
A: An example is BF₃, which is nonpolar, as the dipoles cancel out due to its trigonal planar shape.
Flashcard 31
Q: How does electronegativity affect bonding?
A: Differences in electronegativity between atoms determine bond polarity, with greater differences leading to more polar bonds.
Flashcard 32
Q: What is the difference between sigma and pi bonds?
A: Sigma bonds form by the head-on overlap of orbitals, while pi bonds form by the sideways overlap of p orbitals.
Flashcard 33
Q: What is the molecular geometry of AX₂?
A: Linear, with bond angles of 180°.
Flashcard 34
Q: What is the molecular geometry of AX₄?
A: Tetrahedral, with bond angles of 109.5°.
Flashcard 35
Q: What shape does a molecule with AX₄E have?
A: Trigonal pyramidal, with bond angles less than 109.5° due to the lone pair.
Flashcard 36
Q: What is the electron geometry of AX₄?
A: Tetrahedral, as it accounts for both bonding and lone pairs.
Flashcard 37
Q: What happens in resonance structures?
A: Resonance occurs when there are multiple valid Lewis structures for a molecule, showing delocalization of electrons.
Flashcard 38
Q: What is the AX notation?
A: AX notation is a way to represent molecular shapes, where "A" is the central atom, "X" is the number of bonding atoms, and "E" is the number of lone pairs.
Flashcard 39
Q: What is the molecular geometry of AX₂E₂?
A: Bent, with bond angles of less than 109.5° due to the two lone pairs on the central atom.
Flashcard 40
Q: What is the relationship between electron geometry and molecular geometry?
A: Electron geometry considers both bonding and lone pairs, while molecular geometry only looks at bonded atoms.
Flashcard 41
Q: How does the steric number affect molecular geometry?
A: The steric number (sum of bonding pairs and lone pairs) determines the electron geometry, which in turn dictates the molecular geometry.
Flashcard 42
Q: What is the molecular geometry of AX₃E?
A: Trigonal pyramidal, with bond angles less than 109.5° due to the lone pair.
Flashcard 43
Q: How do you determine the steric number?
A: The steric number is the sum of bonding pairs and lone pairs on the central atom.
Flashcard 44
Q: What is the hybridization of a molecule with AX₂?
A: sp hybridization, forming a linear shape.
Flashcard 45
Q: What hybridization is expected for AX₃?
A: sp² hybridization, forming a trigonal planar shape.
Flashcard 46
Q: What is the hybridization of a molecule with AX₄?
A: sp³ hybridization, forming a tetrahedral shape.
Flashcard 47
Q: What causes a molecule to have a dipole moment?
A: A molecule has a dipole moment if it has polar bonds and an asymmetrical shape, creating a separation of charge.
Flashcard 48
Q: What is the molecular geometry of AX₃E₂?
A: T-shaped, with bond angles of 90° and 180°.
Flashcard 49
Q: What type of bonding occurs in ionic compounds?
A: Ionic bonds, formed by the transfer of electrons between atoms with large differences in electronegativity.
Flashcard 50
Q: How does the AXE notation differ from molecular shape?
A: The AXE notation refers to the arrangement of electron pairs, while molecular shape refers specifically to the positions of atoms in a molecule.