Activate Alert when closing Safari

Hey guys,

I'm very new on my Macbook Pro Retina and the keyboard layout is new for me and every time when i have to enter the @ I type cmd+q, because this was the layout for my old Acer notebook. And you know what happens when you press those buttons, yessss, Safari closes 😁 and all of my Tabs closes too. I used Firefox on my Acer and when I closed the browser it asked me if I'm really sure to close all the tabs....

My question: How can i activate the alert/warning message in Safari 6.0.2, so that Safari will ask me, if I'm sure to close all Tabs; I can't find this option in the settings 😟

Specs:

Macbook Pro Retina

Safari 6.0.2

Mac OS X 10.8.2

thank you in advance,

Andy