nomenclature and isomerism

• what is an isomer?

  molecules with the same molecular formula
• what i a structural isomerism?

  same molecular formula, different structure form
• what is a positional isomer?

  different position of functional group
• what is a chain isomer?


  different chain
• what is a functional group isomer?

  different functional group
• what is stereoisomerism?


  same molecular formula, same structural formula, different in 3D space
• what are geometric isomers?

  e/z isomers with alkenes