iMac 6,1 as monitor for Macbook Air 11'' ?

Hi everyone,

I have an old iMac "core 2 duo" 2,16 24'' (also know as the iMac 6,1), with OS version 10.6.8 which is getting old. I would like to use it as a monitor for my Macbook air 11'' (with the latest Yosemite).

1) Is it possible?

2) What do I need?

I know it is possible with newer versions of the iMac but I'm not too sure mine can do the "cmd + F2" thing. And before buying expensive cords to link them, I want to be sure it can be done 🙂

Thank you very much for your time and your help!!