Atomic Models Chemistry
Why is Lego™ the most ingenious toy in the world? Excerpt from Sophie’s World© By Jostein Gaarder
Models Empedocles, ~450 BC Democritus, 400 BC John Dalton, ~1800 Thomson Model, 1904 Nagaoka / Rutherford Model, 1911 Robert Milliken Bohr Model, 1913 Schrodinger’s Model, 1925
Why?
Empedocles, ~450 BC Earth, Air, Fire, Water Love and Strife changes the elements Love unites elements Strife drives elements apart Aristotle called him “The Father of Rhetoric”
Democritus (~400 BC) The Happy Philosopher “Atomos”-cannot be divided “The Void” Nothing exists except atoms and empty space; everything else is opinion.
Democritus (~400 BC) Nothing exists except atoms and empty space; everything else is opinion.
John Dalton 1766 – 1844 English, Born a Quaker and the son of a weaver Did research on color blindness, atomic theory, gasses, atomic weights, meteorology Proposed a version of the periodic table Proposed Dalton’s Atomic Theory
John Dalton Proposed a version of the periodic table
Dalton’s Atomic Theory Elements are made of tiny particles called atoms All atoms of a given element are identical The atoms of a given element are different from those of any other element Atoms of one element can combine with atoms of other elements to form compounds. A given compound always has the same relative numbers and types of atoms (The Law of Constant Composition). Atoms are indivisible in chemical processes. That is, atoms are not created or destroyed in chemical reactions. A chemical reaction simply changes the way atoms are grouped together.
- 1897
- 1897
Hantaro Nagaoka 1904 Japanese physicist from Nagasaki Suggested that an atom has a central nucleus to which electrons orbit like the rings of saturn. This is the “Typical” model initially used to describe the atom
Ernest Rutherford 1871 - 1937 Ernest Rutherford's family emigrated from England to New Zealand before he was born. They ran a successful farm near Nelson, where Ernest was born. One of 12 children, he liked the hard work and open air of farming, but was a good student and won a university scholarship. After college, he won another scholarship to study at Cambridge University in England -- a turning point in his life. There he met J.J. Thomson (who would soon discover the electron), and Thomson encouraged him to study recently- discovered x-rays.
Rutherford reasoned that all of the atoms positively charged particles were contained in the nucleus. The negatively charged electrons were scattered outside the nucleus around the atoms edge.
Robert Millikan 1910 (1913) Determined the charge and energy of the electron. + -
Niels Bohr Model of the atomic structure,1913
Louis De Broglie 1924 French physicist Proposed that electrons have some properties of waves based on work by Einstein and Planck (Wave-Particle duality duality of light).
Erwin Schrodinger 1925 The Founder of Quantum Wave Mechanics Determined an equation to determine the location of an electron based upon probability Credited for development of the Quantum Mechanical Model of the atom
Models Empedocles, ~450 BC Democritus, 400 BC John Dalton, ~1800 Thomson Model, 1904 Nagaoka / Rutherford Model, 1911 Robert Milliken Bohr Model, 1913 Schrodinger’s Model, 1925