Atomic Construction

• Neutrons have no charge and are also located in the nucleus.
• Protons are positively charged particles found in the nucleus.
• Dalton's Atomic Theory: All matter is made up of tiny particles called atoms, which are indivisible and indestructible.
• Postulate 1: All matter is made of tiny particles called atoms
• Postulate 3: Compounds are formed by combining two or more elements
• Postulate 4: Chemical reactions involve rearrangement of atoms but not creation or destruction of them
• Postulate 2: Atoms cannot be created or destroyed
• Postulate 5: The properties of an element depend on its atomic structure
• John Dalton was born in England in 1766 and died there in 1844.
• Postulate 6: No. of atoms are constant in a compound.
• Dalton's Model of the Atom contains that:

  matter is made up of atoms.

  Atoms in a specific element are identical in mass and properties.

  Formed by the combination of 2 or more atoms.
• Plum Pudding (J.J Thomson)

  discovery in 1904 of negatively charged electrons, without the nucleus discovery.

  He believed the counterbalance for +charges would have been a soup of diffusion of floating particles.
• Rutherford’s Gold Foil Experiment (Niels Bohr)
• Electron Cloud Model (Ernest Rutherford)
• Rutherford's Model of the Atom:

  states that the nucleus contains a relatively high central charge concentrated to a small volume of electrons called the bulk of mass

  this is surrounded by lighter electrons.
• Bohr's Model of the Atom:

  + charged nucleus surrounded by - charged electrons, which travels in a circular orbit.

  Electrons jump between orbits accompanied by an emitted/absorbed amount of energy.
• Ground State: normally occupied energy level
• Excited State: electrons less-stable by absrbing energy.
• Schrodingers's Model of the Atom

  nucleus surrounded by clouds of electrons (clouds of probability)

  Regions of space: electron orbits
• 1932: James Chadwick discovered the neutron, which is a particle that has no charge and no mass, completing the subatomic particles in making an atom.
• Quarks: Particles that make up protons and neutrons.