Scientists Contributions to the Atom

Question 1

John Dalton

Answer 1

Atomic Theory

Proposed the first atomic theory:
- Elements consists of atoms
- Atoms cannot be created, destroyed, or divided
- Atoms of the same element are identical in size, mass, and other properties

Question 2

J.J Thompson

Answer 2

Discovering the Electron

First provided evidence of electron experiment through Cathode ray experiment
Hypothesized that the ray contains streams of negitively charged particles (electrons)

Able to determine the charge-to-mass ratio of an electron:

Question 3

Robert Milkins

Answer 3

Charge of Electron

Measured charge of electron though oil drop experiment

Question 4

Ernest Rotherford

Answer 4

Nuclear Model

Conducted a gold foil experiment, discovering a dense positive core

positively charged core contians most of the atom’s mass

Question 5

James Chadwich

Answer 5

Discoverly of the Neutron

Discovered that protons and uncharged particles, neutrons made up the nucleus

Question 6

James Maxwell

Answer 6

Theories of Light

Discovered that light is a electromagnetic wave composed of wavelengths that form a spectrum

Question 7

Max Plunck

Answer 7

Quantum Hypothesis

Planck discovered that energy is gained or lost in fixed amounts, rather than in random quantities —> (energy comes in packets)

Question 8

Albert Einstein

Answer 8

Discovery of the Photon

Discovery that light behaves both as a wave and particle
Photons transfers its energy to electron upon collision
Part of energy allows electron to escape, and the rest becomes kinetic energy