Atoms, Elements & Compounds

Atoms, Elements & Compounds

1. Atoms

   • Nucleus is in the middle - contains protons & neutrons
     • Protons positively charged
     • Neutrons no charge
     • Electrons negatively charged
       • Electrons move around nucleus
   • Simplest particle that substances are made from

2. Elements

   • Substance made of only type of atom

3. Compounds

   • Ionic Compound
     • Compounds formed from Metal and non-metal
   • Convalent Compound
     • Just formed from non-metals
     • Can be simple compounds or giant convalent compounds

4. Ions

   • An atom that has gained or lost electrons
   • They are charged
   • They have a full outer shell
   • Become negative (-) if they gain an elecron
   • Become positive (+) if they lose an electron

5. Reactants

   • The substances that are reacted together during a chemical reaction
   • Products
     • The substances that are produced during a chemical reaction

6. Conservation of mass

   • Total mass of the reactant = total mass of the products as atoms are not destroyed in reactions

7. Periodic table

   • Group
     • Vertical columns in the periodic table
     • Elements in the same group have the same number of outer electrons
   • Noble gases
     • The elements/gases in group 0
     • They are unreactive as they already have full outer shells
   • Metal
     • Elements found on the left hand side of the 'imaginary staircase'
     • Metals lose electrons to become positive ions
   • Non-Metals
     • Elements found on the right hand side of the 'imaginary staircase'