1031 Exchange Question

[Steve Dudeck]

I have a question on what I can do out of a 1031 Exchange. I'll use round numbers to look for an answer from you guys.

I have an investment property that I purchased for 100K with 20% down. I am setting up a 1031 Exchange, for the sale of the property at 200K. The new property that we are purchasing is 300K. 

Is my Capital Gains 100K?
Do I have to put down the full 200K from the 1031 Exchange into the new property?
Can I only put down 180K? and keep 20k? What is that 20k subjected to if I can do that?

Thanks for the help! 

Steve