Atomic Structure

Main ideas:
• Key things about atomic structure
• Neutrons, protons, electrons
• The Bohr Model
Notes:
Protons, Neutrons and Electrons
Protons (p) :
• relative mass: 1
• relative charge: 1
Neutrons (n) :
• relative mass: 1
• relative charge: 0
Electrons (e-) :
• relative mass: 0.0005
• relative charge: -1
Atomic Structure Key Points

1. The nucleus of an atom is made up of protons and neutrons.
2. Electrons live on the shells of an atom.
3. The charges of an electron cancel out the charges of a proton, leaving an atom with zero charge.
4. Positive and negative charges are attracted to each other, like a magnet.
   Determining The Amounts Of Protons, Neutrons and Electrons Using The Periodic Table
   Reference : Diagram 3, L1
   • A = Mass Number = Total number of protons and neutrons.
   • Z= Atomic Number = Total number of protons.
   • X = Element Symbol (abbreviation used on the periodic table)
   Protons: Z
   Neutrons: A - Z
   Electrons: Z (charges must be balanced)
   The Bohr Model
   Reference: Diagram 4, L1
   • Purple = Neutron
   • Red = Proton
   • Yellow = Electron
   Summary:
   • Atoms are made up of protons (p), neutrons (n) and electrons (e-).
   • The relative charge of an atom is zero.
   • You can determine the amounts of protons, neutrons and electrons using the periodic table.