1031 Exchange - 3 property rule

[Brian Blahous]

I am in the process of a 1031 Exchange. I have a question regarding the 3-property rule.  Let's say I identify 5 properties and 1 falls through but I still close on the other 4.  Is 100% of the exchange disregarded or only the value of the property that I didn't close on?  For example, lets say I sold my relinquished property for $650,000 and my proceeds with the 1031 QI are $200,000.  If I identify 5 properties at $150,000 each and one falls through but I am able to close on 4 of them for a total value of $600,000, would I have to pay tax on the $50,000 that I failed to roll into a new property, or would the entire exchange be disregarded due to the 3-property rule? Assume use all my proceeds with the QI for down payments on the 4 that are purchased.

Thank you!