7 Atomic Structure

Question 1

J. J. Thompson

Answer 1

Developed the plum pudding/raisin bun model and determines the charge to mass ration (q/m) for these cathode rays. The ratio was the same no matter what material was used for the cathode. Thomson interpreted this as meaning that all substances contained the same small discretely charged particles. (Electrons)

Question 2

Rutherford

Answer 2

Developed the Planetary (Nuclear) Model of the Atom. Gold foil scattered a beam of alpha particle. Most went directly through, few scattered at a small angles, very few scatter at large angles (page 284). Interpreted the atom to be mostly empty space with an extremely small positive nucleus with electrons orbiting it.

Question 3

DeBroglie

Answer 3

Suggested that since waves can act like particles, perhaps particles could act like waves.

Question 4

James Franck and Gustav Hertz

Answer 4

Provided more evidence for the quantized structure of the atom. They supplied energy to the atom through collision with a fast moving electron.

Question 5

Dalton (1810)

Answer 5

Proposes the atomic theory, where atoms are small indivisible, indestructible particles. Atoms are neither created nor destroyed, just rearranged. Explained laws of conservation of matter, definite composition and multiple proportions.

Question 6

Mendeleev

Answer 6

Made the original periodic table with the 63 known elements

Question 7

Geisser

Answer 7

Made the vacuum tube (CRT)

Question 8

Thomson and Crookes

Answer 8

Used the CRT to determine q/m ratio for an e- theory. They equated electric and magnetic field and measured the radius of curvature.

Question 9

Milikan

Answer 9

Determine the elemental charge of the oil drop experiment

Question 10

Thomson

Answer 10

The raisin bun model. Electrons embedded in a positive trough like field.

Question 11

Rutherford (1922)

Answer 11

Planetary model. Alpha particles were shot towards a gold foil and most when through, some reflected off at small angles, and very few reflected off at large angles giving him the conclusion that the atom is mostly empty space with an extremely small positive nucleus and electrons orbiting it.

Question 12

Bohr

Answer 12

Energy level model allowing only certain energy levels. Energy in an atom is quantized.

Question 13

DeBroglie (1924)

Answer 13

Standing wave model. Particle can have wave properties related to momentum. ( constructive while number interference)