PRESENTATION OUTLINE
DEMOCRITUS- 465BC
- Hypothesized that atoms cannot be destroyed
- Or differ in size, shape, and temperature
- They are always moving
- Invisible and infinite number of atoms
WHAT HE CAME UP WITH
- All matter consists of invisible particles called atoms
- Atoms are indestructable
- Atoms are solid but invisible
- They are homogenous
- Differ in size, shape, mass, position, & arrangement
ANTOINE LAVOISIER- 1743
- Came from a wealthy family
- Inherited large fortune at 5 when mother died
- Specializes in mathmatics, botany, astronomy, & chemistry
- Studied physiology of respiration
JOHN DALTON- 1766
- Was an english chemist, physicist, and meterologist
- Best known for development of Modern Atomic Theory
Law of Conservation of Mass(1785)
States that matter can be changed from one form into another, mixtures can be separated or made, and pure substances can be decomposed, but total amount of mass remains the same.
-Antoine Lavoisier
DALTONS ATOMIC THEORY- 1808
- All matter is made of atoms. They are indivisble and indestructible
- All atoms of a given element are identical in mass and properties
- Compounds are formed by combination of 2 or more diff atoms
- A chemical reaction is a rearrangement of atoms
Dmitri Mendeleev (1834)
He formulated the periodic law and created his own version of the periodic table of elements
Robert Milikan (1868)
Made many discoveries in fields of electricity, optics, and molecular discoveries. Major success was the charged carried by an electron
Ernest Rutherford (1871)
Was a chemist and physicist. First to split the atom and was awarded the 1908 Nobel Prize in chemistry for his theory of Atomic Structure.
Neils Bohr (1885)
He worked under JJ Thomson. Added the idea that when atoms absorb energy, the electron will jump energy levels.
Erwin Schrödinger (1887)
Won the Nobel Prize. Developed a number of fundamental results in the field of quantum theory. He formulated the wave equation.
Henry Moseley (1887)
He contributed the science of physics, was the justification from the physical law of previous empirical chemical concept of the atomic number
James Chadwick (1891)
Was an English physicist. Awarded the 1935 Nobel Prize in physics for his discovery on the neutron in 1932
JJ Thomson (1897)
He discovered the electron and showed that electrons have a negative charge and came from ordinary matter
Cathode Ray Tube (1897)
A specialized vacuum tube in which images are produced when an electron beam strikes a phosphorescent surface. Invented by Ferdinand Braun
Plum-Pudding (1904)
Negatively charged electrons(plums) were mixed with positive charges(pudding). Explains neutrality of bulk material yet allows the flow of electric charges
-JJ Thomson
Gold foil (1909)
An experiment intended to determine the angles through which a beam of alpha particles would scatter after passing through a thin foil of gold. This led to atom having a nucleus.
Quantum Mechanical Model(1913)
Based on theory(matter also has the properties associated with waves) model of atoms uses complex shapes of orbitals and volumes of space in which there is likely to be an electron