The modern model of the atom is a modification of the Bohr atom. It is commonly referred to as the wave-mechanical atomic model. The name is derived from the fact that electrons can no longer be viewed as merely particles that behave according to classical laws of physics (i.e. mechanics). Experiments conducted at the turn of the century had demonstrated that electrons, due to their small size, must also have wave properties; hence, wave-mechanical atomic model is used to describe the most modern model for the structure of an atom.
The major ramification of the wave-mechanical model is that the electrons can no longer be pinpointed to exact locations. Instead, the electrons are believed to occupy electron clouds surrounding the nucleus. These electron clouds are also referred to as orbitals, and these orbitals represent the most probable location of finding an electron.
The wave-mechanical model for a hydrogen atom in the ground state is shown to the right. The darker the shading in the representation of the electron orbital indicates that there is a higher probability of finding an electron there. However, according to the wave-mechanical model, it is impossible to know the exact location of an electron at any given time.
