Final answer:
The phi and psi values typically pertain to biomolecule torsion angles, but in a chemistry context, they could refer to properties such as electronegativity or atomic radii. Without more context, it's challenging to provide accurate information for elements labeled 9c and d.
Step-by-step explanation:
Regarding the question about approximating the phi and psi values for the central elements of 9c and d, there seems to be a miscommunication or typo as phi and psi values typically refer to torsion angles in biomolecules such as proteins, not elements. In a chemistry context, you might be referring to the Pauling electronegativity values or atomic radii of the elements labeled 9c and d from the periodic table. Since the periodic table elements are not usually labeled in this manner, it makes it difficult to provide an exact answer without more context. If '9c' and 'd' refer to specific elements on the periodic table, please clarify, and for general electronegativity or atomic size trends, elements in the d-block (transition metals) tend to have smaller atomic radii and higher electronegativities than s-block elements.
The complete question is:approximate the phi,psi values for the central elements of 9c and d.