Hey,
Can i connect the Raspberr pi with the arduino Uno. I will use the raspbery for the wifi and the arduino for his pins. If it can can i make the old programs with arduino and use my raspberry as a PC ?
help plz 
Yes you can connect the two together, just use the USB cable is simplest.
You can not do everything with the Pi that you can do with the arduino, because of the Linux operating system kills anything real time. You also can not make the Pi into an I2C slave device.
thx