Chemistry 6

• Atom


  The basic unit of matter
• Subparticles of an atom

  • Proton
  • Neutron
  • Electron
• Proton


  • Positive particle found in the nucleus
• Neutron


  • Neutral particle found in the nucleus
• Electron


  • Negative particle found in orbitals (or shells) outside of the nucleus
• Everything is made out of atoms
• Every atom possesses three basic subparticles: proton, neutron, and electron
• Element


  Matter composed of atoms with the same number of protons
• Elements in the human body

  • Carbon (C)
  • Hydrogen (H)
  • Oxygen (O)
• Atoms of different elements contain different numbers of protons, electrons, and neutrons
• Atoms of different elements

  • Hydrogen: 1 proton, 1 electron
  • Carbon: 6 protons, 6 neutrons, 6 electrons
• Periodic table


  Tells us everything we need to know about each of the different known elements and helps us to understand how the different elements behave
• Atomic number


  • Indicates the number of protons that an atom possesses in its nucleus
• The number of protons tells you what the element is, and each element has its own unique atomic number
• Atoms are electrically neutral, meaning the number of positive charges (protons) must be equal to the number of negative charges (electrons)
• Atomic mass


  Indicates the number of protons & neutrons found in the nucleus of an atom
• Calculating the number of neutrons

  #neutrons = atomic mass - #protons
• Periods on the periodic table

  • Tell us how many orbitals are around the nucleus of an atom
  • The number of elements in a period tells us the maximum number of electrons that can go into an orbital
• Constructing a Rutherford-Bohr model of an atom

  Draw a circle for the nucleus and determine #protons

  2. Determine # orbitals by looking at the period number

  3. Determine # electrons (same as atomic number) and put them into orbitals according to the 2,8,8,2 rule
• Lewis notation


  Only shows the valence electrons of an atom, which are the electrons in the outermost orbital
• Steps to create a Lewis structure


  Write chemical symbol

  2. Draw valence electrons around symbol