Rutherford's Atomic Model and Disintegration

Rutherford's Atomic Model

• Rutherford's work challenged previous atomic models
• He fired positively charged particles at a thin gold foil
• Most particles passed through, some were deflected, and some bounced back
• This suggested a dense, positively charged nucleus at the atom's center
• The atom is mostly empty space
• Electrons orbit around the nucleus

Atomic Disintegration

• Atoms release smaller particles, becoming smaller
• Rutherford proposed that radiation is a product of this disintegration
• Different radioactive materials have different disintegration rates
• "Half-lives" describe the time it takes for a material to reduce by half

Inside the Atom

• Rutherford's famous discovery was made at the University of Manchester in 1907
• The accepted atomic model at the time was the "plum pudding" model (Thomson)
• Thomson's model depicted a diffuse cloud of positive charge with embedded electrons
• Rutherford's gold foil experiment challenged this model
• Calculations demonstrated that the atom's positive charge and mass are concentrated in a tiny nucleus
• Rutherford's model likened the atom to a miniature solar system

Radical Shift

• Rutherford proposed a new atomic model in 1911
• The model emphasized empty space with electrons orbiting a tiny nucleus
• The nucleus held the atom's mass and positive charge
• This was a significant leap in understanding atomic structure

Niels Bohr

• Bohr collaborated with Rutherford
• He helped clarify atomic structure and challenged the classical physics model
• Bohr proposed that electrons have specific energy levels
• Electrons can transition to higher/lower energy levels by absorbing/emitting energy quanta

Atomic Nucleus and Proton

• Rutherford discovered that nitrogen and other light elements emit hydrogen nuclei when bombarded with alpha particles
• Hydrogen nuclei, later named protons, have a positive charge
• Protons are fundamental building blocks of atomic nuclei
• Rutherford also predicted the existence of neutral particles (neutrons) to balance the positive charge of the nucleus

Synthesis of Elements

• Elements can be synthetically created in labs
• Hydrogen is the simplest element
• An element, named Rutherfordium, was discovered after Rutherford