Rank-ordering unfamiliar elements is a common task in chemical reasoning
CHEMISTRY · Multi-part · AP · Chemistry · Atomic Structure and Properties · Atomic Structure and Properties
Problem
Rank-ordering unfamiliar elements is a common task in chemical reasoning. Consider the three elements listed below, none of which are adjacent to each other in the periodic table.
• Calcium • Phosphorus • Selenium
Answer the following questions about these elements.
(a) Arrange the three elements in order of increasing electronegativity. Write the chemical symbols separated by “<” symbols (for example, X < Y < Z).
(b) Provide a detailed justification for the order you chose, explicitly citing both group and period considerations as well as any relevant shielding or nuclear-charge arguments.
(c) For the binary compounds CaSe and PSe, predict which bond is expected to be more polar. Explain your reasoning with reference to your ranking in part (a).