Chadwick discovered a new particle in the nucleus called the neutron through experiments bombarding various elements with alpha particles. The neutron was predicted by Majorana due to its lack of an electrical charge, allowing it to penetrate nuclei without overcoming electromagnetic repulsion like protons. Using Rutherford's zinc shield technique, Chadwick determined neutrons could enter even the heaviest element nuclei, helping establish the neutron as a key part of the nuclear model and defining the atom's mass.

1. James Chadwick
Ariana, Colby, and Lindsey

2. Previous model - Rutherford

3. Chadwick’s Experiment
– Chadwick discovered an unknown particle in the
nucleus.
– Predicted by Ettore Majorana, who found it
because of its lack of electrical charge
– Chadwick used Rutherford’s zinc shield and
inferred neutrons do not need to overcome any
coulomb barrier and can therefore penetrate and
enter the nuclei of even the heaviest elements.

4. Rutherford’s
experiment

5. Chadwick’s Model
ft. Bill Nye the ‘Psy’ence guy

6. • Chadwick discovered neutrons in the nucleus,
which helped define atom’s mass.