There are 6 episodes in the Star Wars series, not 7. In chronological order by release date, they are...
"Star Wars - Episode IV - A New Hope" (Renamed later, to distinguish it from just "Star Wars")
"Star Wars - Episode V - The Empire Strikes Back"
"Star Wars - Episode VI - The Return of the Jedi"
"Star Wars - Episode I - The Phantom Menace"
"Star Wars - Episode II - Attack of the Clones"
"Star Wars - Episode III - The Revenge of the Sith"
For more information, please see the Related Link below.