Chemistry (Atomic Model)

• Atomic structure refers to the structure of the atom
• Atom


  • The basic unit of matter that is used to understand the physical and chemical properties of the periodic table of the elements
  • Approximately 10 000 000 times smaller than a single grain of sand
  • Approximately 1 000 000 000 times smaller than a medium-sized orange
• Nucleus


  The central part of an atom that contains protons and neutrons
• Protons


  Positively (+) charged particles located in the nucleus
• Neutrons


  Neutral (no charge) particles also found in the nucleus
• Electrons


  Negatively (-) charged particles orbiting the nucleus in electron shells or energy levels
• Subatomic particles and their properties

  • Proton: Relative mass 1, Charge 1+
  • Electron: Relative mass 1/1850, Charge 1-
  • Neutron: Relative mass 1, Charge None (0)
• Virtually all the mass of an atom is in its nucleus
• All the positive charge is concentrated in the nucleus. All the negative charge is spread among the electrons surrounding the nucleus
• An atom is electrically neutral, i.e. the positive charge is equal to and balanced by the negative charge so the number of protons in the nucleus is the same as the number of electrons surrounding the nucleus
• Protons help to identify the atom - different elements will have a different number of protons in the nucleus
• The number of protons in an atom is equal to the atomic number in the periodic table
• The number of neutrons in an atom is equal to the atomic mass minus the atomic number
• There are the same number of electrons as there are protons in the nucleus, so the number of electrons in an atom can also be found by reading the atomic number on a periodic table
• The nucleus is the middle of the atom and is made up of protons and neutrons
• Isotope


  A variation on the atomic structure of an element with the same number of protons and electrons, but a slightly different number of neutrons
• Atoms


  Smallest unit of a chemical element, consisting of a nucleus and one or more electrons
• Elements


  • Hydrogen
  • Oxygen
  • Carbon
• Elements


  Substances composed of atoms with the same number of protons in their nuclei
• Compounds


  • Water
  • Carbon dioxide
  • Sodium chloride
• Compounds


  Substances composed of atoms of two or more different elements chemically bonded together
• Mixtures


  • Air
  • Saltwater
  • Brass
• Mixtures


  Substances composed of two or more different substances physically mixed together
• Ions


  Charged particles formed when atoms gain or lose electrons
• Cations


  Positively charged ions
• Anions


  Negatively charged ions
• Ion examples


  • Sodium ion
  • Chloride ion
• Elements used in industry

  • Iron in steel production
  • Aluminium in aerospace
  • Silicon in semiconductor manufacturing
• Industrial compounds


  • Water
  • Ammonia in fertilizer
  • Sulfuric acid in chemical manufacturing
• Mixing processes in industry

  • Food processing
  • Pharmaceuticals
  • Cosmetics
• Industrial uses of ions

  • Electroplating
  • Water treatment
  • Battery technology