Im new at Unity

ive been using blender for the past few years so im new at unity so i have a few questions.

1.can you use particle systems in the games? 2. im kinda new at scripting i can do stuff like simple movment scripts but with other stuff im inferior. So can some one send me an example of a collision script to collide with some random property or mesh and delete the object

  1. Google this: unity3d particle systems

  2. Google this: unity3d collision script

  3. RTFM this: http://unity3d.com/support/documentation/Components/comp-ParticlesGroup.html and http://unity3d.com/support/documentation/ScriptReference/Collider.html