A student uses photoelectron spectroscopy to compare equal numbers of gas-phase \(\text{Al}\) atoms and \(\text{Al}^{+}\) ions under identical conditions. In each spectrum, peak intensity is proportional to the number of electrons in the corresponding subshell. The \(1s\) peaks are omitted from the graph.

Which statement best explains why the \(3s\) peak undergoes a larger shift than the \(n=2\) peaks when \(\text{Al}\) is oxidized to \(\text{Al}^{+}\)?