Thomson's Atomic Model Explained

J.J. Thomson's model of the atom, often called the "plum pudding" model, proposed that an atom consists of a sphere of positive charge. Embedded within this positive sphere are negatively charged electrons, distributed throughout the atom.

Analysis of Options Based on Thomson's Model

Let's examine each statement in the context of Thomson's Atomic Model:

• Option 1: Electrons are fixed in the orbits. This is incorrect. Thomson's model did not propose fixed orbits for electrons; that concept was introduced later, notably by Bohr.
• Option 2: Electrons are concentrated in the nucleus. This is incorrect. The concept of a dense, positively charged nucleus was proposed by Rutherford, not Thomson. Thomson's model featured a diffuse positive charge.
• Option 3: Electrons are spread randomly in a positively charged sphere. This statement accurately describes Thomson's model. The electrons (like plums) are embedded within a uniform, positively charged substance (the pudding).
• Option 4: Electrons are attached to neutrons. This is incorrect. Thomson's model predates the discovery of the neutron. His model focused on the distribution of positive charge and electrons.

Therefore, the only statement that correctly aligns with Thomson's Model of the Atom is that electrons are distributed within a sphere of positive charge.