Atomic Structure

• Atoms are the building blocks of matter that make up

  everything that exists in our world.
• Democritus - Atomos ar something that cannot be broken down any further.
• Aristotle - Matter are made up of four elements.
• Dalton’s atomic Theory ( The Solid Sphere Model): proposed atomic theory of matter in 1803, atom as a solid, indestructible sphere
• John Dalton - he is known as one of the fathers of

  modern physical science.
• Joseph John Thomson - He discovered electrons using a cathode ray tube and proposed the plum pudding/raisin bun model
• The Raisin Bun Model/Plum pudding model: Spherical cloud of positive charge with electrons littered on it.
• Ernest Rutherford - Nuclear Model of an Atom

  
• Dalton’s atomic Theory ( The Solid Sphere Model)

  • All matter is composed of extremely small, indivisible, indestructible particles called atoms.
  • All atoms of each element is exactly alike, but they differ from atoms of other elements. The atoms of different elements have different mass and other properties.
• Dalton’s atomic Theory ( The Solid Sphere Model) 3. When atoms of different elements combine to form a compound, the constituent atoms are always present in the same fixed numerical ratio.

  4. A chemical reaction involves a rearrangement of atoms. No atom is created or destroyed.
• Ernest Rutherford ( Nuclear Model of an Atom)

  1. The gold atoms in the foil must be mostly

  consisted of empty space because most of the

  α (alpha) particles were able to penetrate the

  foil. 2. An atom has a positive, central core which he later on called a nucleus ( which means “little nut” in Latin), where most of its mass is intense. The nucleus was so dense that the alpha particles bounce off of it.
• Ernest Rutherford ( Nuclear Model of an Atom)

  3. The negatively charged electrons were so tiny which enabled them to circulate around the nucleus of an atom. The electrons spread out at such great distances from the nucleus.
• Neils Bohr ( Planetary Model of an Atom)

  • In his study of black body radiation , Planck concluded that at least in some cases, energy could be emitted in discrete packages which he called quanta, and not in continuous waves.
• Erwin Schrödinger - Quantum Model
• James Chadwick - Discovered the neutron