ASU BCH 463 (BCH463) Biophysical Chemistry – Module 4 Homework | Questions & Answers | Latest 2026–2027.

BCH 463: Biophysical Chemistry — Module 4 Homework 1. Pi bonding occurs in each of the following molecular species EXCEPT: A. CH₄ B. C₆H₆ C. C₂H₄ D. CO₂ 2. To better explain the H–O–H bond angle as 104.5 degrees rather than 90 degrees, what is the hypothesis used in the VB theory? A. Promotion B. Promotion and hybridization C. Resonance D. Hybridization 3. What kind of orbital hybridization does the propene, CH₃CHCH₂, have according to the VB theory? A. sp B. sp and sp³ C. sp and sp² D. sp² and sp³ 4. A pi bond is the result of the: A. Sidewise overlap of the two parallel p orbitals B. Overlap of two p orbitals along their axes C. Overlap of an s and a p orbital D. Overlap of the two s orbitals 5. How many sigma bonds in a triple bond? A. 3 B. 1 C. 2 D. 0 6. From the above question, how many pi bonds in a triple bond? A. 0 B. 1 C. 2 D. 3 7. Which statement is false? A sigma molecular orbital: A. May result from overlap of one s and one p atomic orbitals B. May result from overlap of p atomic orbitals along the intermolecular axis C. May be either bonding or antibonding D. May result from overlap of p atomic orbitals perpendicular to the intermolecular axis 8. The bond order is defined as half of the difference between the number of electrons in bonding and antibonding orbitals. Carbon monoxide has ten bonding electrons and four antibonding electrons. It then has a bond order of: A. 2.5 B. 6 C. 2 D. 3 9. From the above question, what is the bond order in O₂⁺? A. 3.5 B. 2.5 C. 1.5 D. 2.0 10. Which one of the following statements is false? A. MO are generally described as being more delocalized than hybridized atomic orbitals. B. MO theory involves the energy configuration for molecular orbitals. C. VB theory requires the orbital hybridization hypothesis for the modification. D. For two atomic orbitals, the energy of the bonding orbital is always lower than the antibonding orbital. 11. Antibonding molecular orbitals are produced by: A. Constructive interference of atomic wavefunctions B. Destructive interference of atomic wave functions C. The overlap of the atomic orbitals of two negative ions D. None of these 12. From the above question, bonding orbitals are produced by: A. None of these B. Destructive interference of atomic wavefunctions C. Constructive interference of atomic wavefunctions D. The overlap of the atomic orbitals of two negative ions 13. The overlap integral (S=∫ψ A ​ ψ B ​ dτ) describes the overlap of the two atomic orbitals. In the following figure, what will be the possible S value? (purple: s orbital; brown: p orbital) A. Large but cannot be exactly determined from this figure B. Large but less than 1.0 C. 0.5 D. 0 Note: Question 13 refers to the orbital-overlap diagram shown on page 4 of the PDF. 14. From the above question, what is the S value for the attached figure? A. Large but cannot exactly know the value from this figure B. 0 C. 0.5 D. Large but less than 1.0 Question 14 refers to the orbital-overlap figure on page 5. 15. The delta bond (or delta combination) can only be formed by which orbital? A. d B. f C. p D. s 16. The Hartree-Fock method approximates the multiple-electron wavefunction by using: A. A linear combination of atomic orbitals (LCAO) B. A sum of independent electron densities C. A product of single-electron wavefunctions D. A Slater determinant of single-electron wavefunctions 17. Which of the following is the primary reason why the Schrödinger equation cannot be solved exactly for multi-electron atoms? A. The Born-Oppenheimer approximation breaks down B. The nucleus has a finite size C. Relativistic effects become significant D. Electron-electron repulsion terms cannot be separated 18. A Hartree product wave function for a multi-electron system is: A. Antisymmetrized under particle exchange B. A sum of Slater determinants C. The exact solution to the many-electron Schrödinger equation D. A simple product of one-electron wave functions 19. What mathematical construct ensures that a multi-electron wave function satisfies the Pauli exclusion principle? A. Configuration interaction B. Hartree product C. Antisymmetric property for Slater determinant D. Basis set expansion 20. Which set of quantum numbers (n,l,m l ​ ) is NOT possible for a d orbital? A. (5, 2, 1) B. (4, 2, 3) C. (3, 2, −2) D. (3, 2, 0) 21. The p x ​ orbital is oriented along which axis? A. y-axis B. x-axis C. z-axis D. It has no specific orientation. 22. In multi-electron atoms, which orbital penetrates closest to the nucleus? A. 3p B. 3s C. All penetrate equally D. 3d 23. The two lobes of a p orbital have: A. The same sign (phase) of the wave function B. Opposite signs (phases) of the wave function C. Zero amplitude at all points D. No phase relationship