Atomic structure

• An atom is the smallest particle of an element that can exist.
• A molecule is a group of atoms chemically bonded
• Structure of an atom

  
• Proton - +1 - relative mass 1
• Electron - -1 - relative mass 0.0005
• Neutron - 0 - relative mass 1
• periodic table

  
• An isotope is an atom of the same element with the same number of protons but different number of neutrons
• Relative atomic mass is the average mass of an atom of an element compared to 1/12th the mass of an atom of carbon-12
• (Mass X abundance)+(mass X abundance)/100= Ar