2.4 Rutherford
Ernest Rutherford used α particles to find the structure of atoms. Most particles penetrated the gold foil undeflected, but some were deflected at a large angle, while others bounced back in the direction from which they had come.
Rutherford proposed the nuclear model where the positive charge is concentrated in the nucleus. The nucleus accounts for most of an atom’s mass (extremely dense central core in the atom).
- A typical atomic radius is about 100 pm
- A typical nucleus has a radius of about 5×10–3 pm
- 1 pm = 1×10–12 m