Physical Science Atomic Structures

• Atoms of the same element have the same number of protons but different numbers of neutrons are known as isotopes.
• Thinking about matter

  Democritus
• Democritus co-originated the though with his teacher _ that all matter is composed of individual elements

  Leucippus
• matter is simply composed of atoms of different weights and is combined in ratios by weight.

  John Dalton
• Atoms are spherical and in motion

  John Dalton
• constructed primitive cathode ray tube which became basis for television

  William Crookes 1870s
• is a vacuum tube containing one or more electron guns

  Cathode-ray tube
• discovered positively charged subatomic particle called proton

  Eugen Goldstein 1886
• In 1886, Eugene Goldstein (1850-1930) discovered evidence for the existence of this positively charged particle. Using a cathode ray tube with holes in the cathode, he noticed that there were rays traveling in the opposite direction from the cathode rays. He called these canal rays and showed that they were composed of positively charged particles.
• discovered X-rays accidentally while testing whether cathode rays could pass through glass.

  Wilhelm Roentgen 1895
• his experiments with cathode ray tubes showed that all atoms contain tiny negatively charged subatomic particles or electrons.

  JJ Thomson
• Thomson proposed the plum pudding model of the atom, which had negatively-charged electrons embedded within a positively-charged "soup.“
• is defined by electrons surrounded by a volume of positive charge, like negatively-charged “plums” embedded in a positively-charged “pudding”

  Plum Pudding Model
• theorized that radioactive particles cause atoms to break down that releasing radiation that takes the form of energy and subatomic particles

  Pierre and Marie Curie
• Pierre and Marie Curie discovered strongly radioactive elements called?

  Polonium and Radium
• She coined the term radioactivity

  Marie Curie
• he introduced the quantum theory

  Max Planck
• quanta are now called what by physicists

  photons
• is the theoretical basis of modern physics that explains the nature and behavior of matter and energy on the atomic and subatomic level.

  Quantum theory
• mathematical equation involving a figure to represent individual units of energy

  quanta
• theories of relativity and hypothesizes the particle nature of light. this was the basis of nuclear energy

  Albert Einstein
• light's energy is related to its oscillation frequency.

  Einstein's light quantum theory
• measured the charge of a single electron known as the elementary charge.

  Robert Millikan
• father of nuclear physics, developed the theory for the structure of atom using a gold foil experiment

  Ernest Rutherford
• Developed the Bohr atomic model, electrons travelling around the nucleus and chemical properties being determined by how many electrons are in the outer orbits

  Neil Bohr
• Neil Bohr integrated what theory? stating that when electrons change orbits they emit a quantum of discrete energy

  Planck Quantum theory
• described how electrons move in a wave form, developed Schrodinger equation

  Erwin Schrodinger
• discovers the neutron component of the atomic nucleus, explaining the nuclear fission of uranium 235

  James Chadwick
• In 1932, the physicist James Chadwick conducted an experiment in which he bombarded Beryllium with alpha particles from the natural radioactive decay of Polonium. The resulting radiation showed high penetration through a lead shield, which could not be explained via the particles known at that time.
• "Father of nuclear chemistry" discovers nuclear fission along with?

  Otto Hahn along with Lise Meitner
• Ottoh Hahn discovered the fission of?

  Uranium
• Fission is the splitting of a heavy, unstable nucleus into two lighter nuclei, and fusion is the process where two light nuclei combine together releasing vast amounts of energy