I've 1 copy of factor v leiden & have a blood clot in my femoral artery as a result of an angiogram, with no flow. will the clot eventually break off?

Not likely: The femoral artery that closed following a procedure is unlikely to open. What usually happens is small arteries called collaterals open up to preserve the circulation in the lower extreme ties. It is often inadequate and most often will require opening the artery by balloon angioplasty/stent or by surgery. This is often done as soon as it is recognized that the femoral artery has closed

Unlikely: If there is "no flow" in the femoral artery, then presumably there are collateral ("bypass") vessels bringing blood to your leg if you are in a stable condition. Most commonly these vessel closures become permanent, with the collaterals growing over time. The clot solidifies and becomes fibrous material that is not fragile or prone to fragmentation.