Atomic Theory

Question 1

Leucippus and his student Democritus

Answer 1

• Year: around 440 BCE
• They first proposed that everything was many of of tiny particles surrounded by empty space
• “Blind guess”

Very very old and greek

Question 2

John Dalton

Answer 2

• Year: 1808
• English
• Proposed an indivisible particle (the atom)
• Concept of atomic theory
• Atomic model

Original, old

Question 3

Joseph John Thompson

Answer 3

• Year: 1897
• English
• Discovered electrons
• Said the atom was a sphere of positive charge embedded with negative electrons (a combination of smaller + and - particles)
• Determined this by the Cathode Ray Tube experiment
• “Plum-pudding model”

Eureka moment, optimist but pretends to be a pessimist, likes worms and pudding

Question 4

Ernest Rutherford

Answer 4

• Year: 1911
• New Zealander
• Every atom has a positively charged nucleus
• Discovered with the gold foil experiment
• Mass is mostly contained in the nucleus
• Thompson’s student
• “Nuclear model”

Happy, rich, strong

Question 5

Neils Henrik David Bohr

Answer 5

• Year: 1913
• Danish
• Discovered the shells surrounding the nucleus where electrons are at large
• Nobel prize winner
• Created the current simple model of an atom
• Electrons are paired and arranged, however they can jump between shells by gaining or losing electrons.
• Also Thompson’s student
• “Planetary model”

Smart, big, bi-polar, yummy cheese

Question 6

Werner Heisenberg

Answer 6

• Year: 1926
• German
• Formulated the “uncertainty principle” (“wave equation”)
• Discovered that it is impossible to determine the exact speed and position of electrons as they move around an atom

Friends with Schrodinger, he’s a snake, lazy, uncertain principal

Question 7

Erwin Schrödinger

Answer 7

• Year: 1926
• Austrian-Irish
• Described hydrogen atoms as clouds of negative charge
• Electrons move around the nucleus in a cloud, not in orbits
• The closer to the nucleus, the higher chance there will be electrons
• Came up with the “Quantum-Mechanical Model”

Multicultural, likes Ant-Man, stormy, doesn’t like circles, likes to be close to people

Question 8

James Chadwick

Answer 8

• Year: 1932
• English
• Discovered that the nucleus also contains neutrons
• Rutherford’s student
• Mass of nucleus is around the mass of protons

Peacemaker/fair, young, expert on neutrals

Question 9

What is atomic theory?

Answer 9

• The study of the nature of atoms and how they combine to form all types of matter
• Different atoms give elements different properties