C1.1 Fundamental Ideas

C1.1 Fundamental Ideas

1. Atoms

   • Make up elements
     • Sorted into groups
       • Periodic Table
       • Groups contain elements with similar properties
     • Elements are represented by a chemical symbol
   • Have a small central nucleus
     • Made up of protons and neutrons
       • Protons have a +1 charge
       • Neutrons have 0 charge
       • Number of protons/ electrons
         • Atomic number
       • Number of protons and neutrons
         • Mass number
     • Surrounded by electrons
       • Electrons have a -1 charge
       • Occupy energy shells
         • 2,8,8
         • Occupy the lowest available energy shell
     • Have no overall charge

2. Periodic Table

   • Elements in groups
     • Same number of electrons in highest energy level
     • Similar chemical properties
   • Group 0
     • Noble gases
       • Unreactive
       • Stable
         • Full shells

3. Chemical Reactions

   • Atoms join together
     • Form compounds
     • Give, take or share electrons
       • Form ions
         • From metals and non metals
       • Form Molecules
         • From non-metals
         • Covalent bonds
   • Represented by word or symbol equations
     • Symbol equations might need to be balanced
   • No atoms made or lost
     • mass of products = mass of reactants