Atomic Structure and Rutherford's Model

Rutherford's Atomic Model

• Rutherford's work in 1902 challenged existing chemical understanding of atomic structure
• He famously fired positively charged particles at a thin sheet of gold foil
• Most particles passed straight through, but some were deflected or bounced back
• This led Rutherford to conclude that atoms are mostly empty space, with a dense, positively charged nucleus at the center
• The positively charged nucleus contained most of the atom's mass

Atomic Structure

• Thomson's plum pudding model: a model of the atom with electrons embedded within a positively charged 'pudding'
• Rutherford's model introduced the concept of a nucleus, containing most of the atom's mass and positive charge
• Electrons orbit the nucleus
• This model revolutionized understanding of matter at the atomic level

Radioactive Decay

• Atoms disintegrate when releasing particles
• Radiation is a byproduct of this process
• Radioactive materials disintegrate at different rates, measured by their half-lives

Atomic Nucleus

• Rutherford discovered that the positive charge and mass of the atom are concentrated within a very small volume, at the center of the atom
• He called this central region the "nucleus"

Proton Discovery

• Rutherford concluded that hydrogen nuclei (protons) are fundamental building blocks of all elements
• Hydrogen atoms are the simplest
• Bombarding other light elements with alpha particles releases hydrogen nuclei
• Protons were postulated to have a positive charge, located in the atomic nucleus

Neutron Discovery

• Neutral particles (neutrons), also found within the nucleus, were identified by James Chadwick in 1932