Does ios 7 slow down a 16 gb iphone?

I'm thinking about getting an iphone. And i want ios 7 on it but not sure if it will slow it down because it might take up alot of space or something
so does it?

If the iPhone is an iPhone four then the answer is most likely yes. Anything 4s and above should be good.

I have had an iPhone 5 for about an year now when i updated to the iOS7 from iOS 6 it did slow down a littel but i got usetoo of it every soon. So the answer is yes very slightly but if you have iPhone 5s then you should be fine because iOS7 is designed for 5s.