What is the difference between T1 and T2 mri scans?

I was just reading my notes and realised I do not adequately know the difference between these two scans. So here are my few questions:

What are the methodologically differences in acquiring them both?

What actually happens to the particles in the brain when each one is performed?

What are the pros and cons of each technique?

I am not a neurosciencey geek so if you could keep explanations sort of simple that would be great.

Thanks