John Dalton proposed the Solid Sphere Model of the atom.

In the Solid Sphere Model, atoms were thought to be tiny, indivisible, solid balls.

The Plum Pudding Model proposed by Ernest Rutherford showed a dense nucleus in the center of the atom.

The Plum Pudding Model described electrons as scattered within a positively charged“ pudding.”

Ernest Rutherford’s Nuclear Model showed that most of an atom’s mass is concentrated in the nucleus.

According to the Nuclear Model, electrons move in fixed circular orbits around the nucleus.

Niels Bohr’s Planetary Model suggested that electrons orbit the nucleus in specific energy levels.

In the Planetary Model, electrons can jump from one energy level to another by gaining or losing energy.

The Quantum Model describes electrons as having exact, fixed paths around the nucleus.

The Quantum Model, developed by Erwin Schrödinger, is the most accurate model of the atom used today.