The Periodic Table

The Periodic Table

1. what is an ion?

   • an ATOM or a group of atoms that has an UNEQUAL NUMBER of protons and electrons
   • positive ion-LOOSE ELECTRONS
   • negative ion-GAIN ELECTRONS

2. THE HALOGENS

   • the most reactive halogen is at the top of the group.
   • Fluorine
     • colourless gas
     • most reactive
   • Chlorine
     • pale green gas
   • Bromine
     • brown liquid
   • Iodine
     • grey purple solid

3. transition metals

   • they are less reactive than the alkali metals
   • have higher melting points than alkali metals
   • stronger and harder than alkali metals
   • USES
     • construction e.g. bridges and cars
       • iron is commonly used
     • to make alloys
     • catalysts
     • pigments