A simultaneous description of nuclear form factors and momentum distributions for ground and collective excited states is presented using a simple liquid drop model with an oscillating nuclear surface. The influence of the nuclear surface diffuseness over nuclear form factors and nucleon momentum distributions for a large region of mass number is investigated. Mean square radii of nuclei in one-phonon excited states are discussed. Quasi-elastic electron scattering y-scaling functions are presented and compared with those extracted from experimental data.