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1. Fundamental ideas in chemistary

   • General info:
     • All substances are made of tiny particles called atoms.
     • An element is a substance that is made of only one type of atom.
     • These are shown in the periodic table of elements.
     • Metals shown on the left, non-metals shown on right.
   • Atomic structure:
     • Protons- found in nucleus, +1
     • Nuetrons-found in nucleus 0
     • Electrons- found in shells -1
   • Atomic number & Mass number
     • The atomic number is the number protons it contains.
     • Mass number is the number of protons and neutrons it contains.
     • to work out the number of neutrons you do top number- bottom number
   • Electronic Structure:
     • first shell-2 second shell-8 third shell- 8
     • The electronic structure of an atom is written using numbers to represent the electrons in each energy level.