Why is my toddler being so defiant all of a sudden?

My 22 month old has always been such an angel until recently. Now his horns are starting to break through. He used to listen pretty well. Now it’s almost as if he looks for reasons to disobey me and do the opposite of what I ask. I know it’s probably considered normal terrible two behavior but I feel like my methods of scolding aren’t working. For example, when he picks up my cell phone and I tell him “You can’t touch mama’s phone. Put it down” he will throw it across the room with a smile on his face instead of putting it down. Then I say “No! That was bad! Now go pick it up and sit in time out.” That always leads to him crying and throwing a fit. I put him on a little stool for 2 minutes in a “time out” but it doesn’t seem like he understands the meaning of it yet. Is he too young to be “punished”? Is there something I can do differently with disciplining him? I am so tired of telling the poor kid “No” and “Don’t” or “Stop”. He is such a happy and smart toddler and when he’s occupied and having fun, he listens and behaves just fine! But as most parents know, I can’t preoccupy him 24/7 or I would never shower or clean my house! Any suggestions are much appreciated :)