Exam 1

Question 1

Matter consists of very small & indivisible particles “ATOMOS”

Answer 1

Democritus 460-370 BC

Question 2

Theory of Essences: Air, Water, Fire, Earth

Answer 2

Aristotle 384-322 BC

Question 3

• Questioned the Aristotelian Theory of Essences
• Insisted in using Scientific Method
• Studied Air

Answer 3

Robert Boyle 1600

Question 4

• Studied Air & Created Soda water
• Instrumental in the discovery of oxygen

Answer 4

Priestly 1700

Question 5

• Claimed discovery of oxygen
• Developed the Conservation of Mass
• Helped device basic inorganic nomenclature & metric system

Answer 5

Lavoiser 1700

Question 6

• Proposed law of definite proportions
• This law helped to support John Dalton’s atomic theory, which stated that elements are composed of unique atoms that combine in specific ratios to form compounds.

Answer 6

Joseph Proust (French Chemist) 1700

Question 7

Postulated:
* Uniqueness of elements
* Law of definite proportions

Answer 7

Dalton Early 1800’s

Question 8

Discovered Radioactivity

Answer 8

Marie and Pierre Currie Late 1800’s

Question 9

• Discovered X-rays
• X-rays allowed scientists to study the internal structure of matter and
  led to the discovery of new subatomic particles, including the electron.

Answer 9

Wilhelm Röntgen (German Physicist) 1800’s

Question 10

• Discovered spontaneous radioactivity

Answer 10

Antoine Becquerel (Professor of Physics in Paris) 1800’s

Question 11

• Used Cathode Ray Tubes (CRT) to find the first subatomic particle of the atom
• Develop the Plum-pudding model of the atom

Answer 11

J.J. Thomson: (English Physicist) ~1897

Question 12

Proved that the charge of each electron was exactly the same

Answer 12

Robert Millikan ~1909’s

Question 13

Used alpha particles to probe the structure of the atom

Answer 13

Ernest Rutherford ~1910’s

Question 14

Together with Rutherford proved the existence of neutrons

Answer 14

James Chadwick ~1932

Question 15

*Worked in black body radiation.
*Don’t radiate continuous range of energies.
*Energy is quantized.
*Accurately predicted (landa) of light radiated by Black body.
*𝐸 = 𝑛ℎ𝜐

Answer 15

Max Planck (German Physicist)

Question 16

*Electromagnetic radiation exits as a stream of particles called
photons.
*The energy of a photon was deduced using Planck’s work, 𝐸𝑝ℎ𝑜𝑡𝑜𝑛 = ℎ𝜐
*Explained photoelectric effect. Energy of photon is quantized.

Answer 16

Albert Einstein 1879-1955

Question 17

*Developed planetary model of the atom.
*e - doesn’t radiate around the nucleus. e - exists in continuous (fixed) energy levels.
*Explained inner working of Hydrogen atom.
*Limitations: e - doesn’t move in circular orbits, only works for H orbits.

Answer 17

Neils Bohr 1885-1962

Question 18

*Defined wave as a particle.
*If light is particle-like, perhaps matter is wavelike landa = ℎ/𝑚𝜐
*Allow for the use of standing waves, where certain frequencies are allowed.

Answer 18

Louis de Broglie (French Graduate Student) 1923

Question 19

*one can not simultaneously determine both the positions and
momentum of an electron. The more accurately we know the exact position, the less accurate we know the speed of the electron
*∆𝑥∆𝑝 ≥ ℎ/4𝜋

Answer 19

Werner Heisenberg 1901-1976

Question 20

*Developed the Schrödinger equation where we relates energy to the space of a system of particles.
*This equation incorporates the wave-like nature of particles
*𝐻̂ 𝜓 = 𝐸𝜓, where 𝜓 is the wave function.
*The solution explains energy levels in atoms and molecules, 𝜓 describes an atomic orbital.

Answer 20

Erwin Schrödinger 1926