Chemistry Quiz

• Atom


  The basic building blocks of all matter and chemistry

  It can combine with other atoms to form molecules but cannot be divided into smaller parts
• Atomic Model

  1.The Atomic Model has changed over time

  
  

  2. For over 2 centuries, scientists have created different models of the atom

  
  

  3. As scientists have learned more and more about atoms, the atomic model has changed.
• Democritus


  Greek philosopher (470-380 B.C.), The Father of modern atomic thought, Proposed that matter could not be divided into smaller pieces forever, Claimed that matter was made of small, hard particles called "atomos"
• John Dalton - 1808


  Created the very first atomic theory, He was an English school teacher who performed many experiments on atoms, Viewed atoms as tiny, solid balls, Atomic theory had 4 statements
• Dalton's Theory


  • Atoms are tiny, invisible particles
  • Atoms of one element are all the same
  • Atoms of different elements are different
  • Compounds form by combining atoms
  • Atoms are small, indivisible
  • Cannot be divided, created, destroyed
  • An element = identical
  • Different elements = different properties
  • Atoms of different elements combine to form compounds
• J.J. Thomson - 1897


  Discovered electrons, First scientist to show that atom was made of even smaller things, Proposed the existence of a (+) particle, Atomic Model was known as the "raisin bun model"
• Thomson's Model


  Atoms are made mostly out of (+) charged material, like dough in a bun, The (-) charged electrons are found inside the (+) dough
• Ernest Rutherford - 1911


  A physicist from New Zealand who studied under Thomson, Discovered protons and the nucleus, Showed that atoms have (+) particles in the center, and are mostly empty space
• Niels Bohr - 1913

  Improved on Rutherford's model, Proposed that electrons move around the nucleus in specific layers, or shells, Every atom has a specific number of electron shells
• James Chadwick - 1932


  Discovered neutrons, He discovered particles with no charge, Neutrons are also found in the nucleus
• The Modern Model - 1932-


  The new atomic model has electrons moving around the nucleus in a cloud, Impossible to know where an electron is at any given time