Yes, atoms would be larger if Planck’s constant h were larger.
Work Step by Step
The de Broglie equation (wavelength = h/p) shows that if h were larger, then for a certain momentum, the electron wavelength would be larger. A whole number of these wavelengths form the standing wave, the electron orbital, that encircles the nucleus. If the wavelength is longer, the circumference is longer, and the atom is larger. This is discussed on pages 608-609, and shown in Figure 32.10.