The quantum-mechanical model predicts that the electron spends more time near the nucleus.
Work Step by Step
In the Bohr model, the electron circles at a fixed distance (the Bohr radius) from the nucleus, and cannot come any closer than that. In contrast, the quantum-mechanical model merely says that the most probable location for the electron is the Bohr radius. A measurement of the electron’s position might find it much closer to the nucleus than the Bohr radius. See Figure 28–6 for a probability cloud of the electron’s location. (The question’s phrasing is rather vague, and an equally good argument could be made that instead the Bohr model “predicts that the electron spends more time near the nucleus” because in the QM model, the electron can sometimes be found much farther away than the Bohr radius.)