Unit 7 GIST - Atoms/Subatomic Particles

What is Brownian motion?

The random motion of particles suspended in a fluid, explained by Einstein as evidence of atoms.

Who discovered the electron?

J.J. Thompson, using cathode-ray tubes

How was the electron's charge measured?

By Robert Millikan through the oil drop experiment.

What did Rutherford's gold foil experiment reveal?

That atoms have a small, dense, positively charged nucleus.

Who discovered the neutron?

James Chadwick in 1932

What is the Bohr model?

A model where electrons orbit the nucleus in fixed, quantized energy levels.

What causes spectral lines?

Electrons jumping between energy levels and emitting/absorbing photons.

What determines the identity of an element?

The number of protons in its nucleus.

Where were hydrogen atoms created?

In the first few minutes after the Big Bang.

How are elements heavier than hydrogen formed?

Through nuclear fusion in stars.

What is the B2FH paper?

A 1957 paper explaining element formation in stars.

What happens to elements in a supernova?

They are dispersed into the universe, forming new stars and planets

What are quarks?

Elementary particles that make up protons and neutrons

What are the 6 flavors of quarks?

Up, down, charm, strange, top, bottom.

What are leptons?

Particles like electrons and neutrinos that are not made of quarks.

What do bosons do?

They carry fundamental forces (e.g., photon, gluon, W/Z bosons, Higgs).

What are the four fundamental forces?

Electromagnetic, strong, weak, and gravitational

What is the Standard Model?

The theory describing all known fundamental particles and interactions (except gravity).

What is String Theory?

A speculative theory suggesting all particles are vibrating strings.

Why is gravity not part of the Standard Model?

It is described by General Relativity and doesn't fit into quantum mechanics.