An element X has a photoelectron spectrum that is described verbally below
CHEMISTRY · Multi-part · AP · Chemistry · Atomic Structure and Properties · Atomic Structure and Properties
Problem
An element X has a photoelectron spectrum that is described verbally below.
• Four distinct peaks are observed.
• Two low-binding-energy peaks occur at 0.54 MJ mol⁻¹ and 0.97 MJ mol⁻¹. Their relative heights are equal and together they account for 4 electrons.
• Two higher-binding-energy peaks occur at 4.2 MJ mol⁻¹ (height corresponding to 2 electrons) and 19.6 MJ mol⁻¹ (height corresponding to 2 electrons).
Binding-energy values increase to the left on the horizontal axis, and the vertical axis reports relative number of electrons.
Answer the following questions about this spectrum and the element it represents.
(a) Identify which of the four peaks represent valence electrons for element X. Justify your answer based on the positioning of the peaks along the binding-energy axis.
(b) Using the relative peak heights, determine the total number of valence electrons in a ground-state atom of X.
(c) Explain how the number of valence electrons you obtained in part (b) helps predict the most common type of chemical reactivity (for example, tendency to lose or gain electrons) of element X.