Will UIsrael attack Iran? More importantly does Israel have the capability to hit the Iranian sites of  Natanz, Fordo, Arak and Isfahan? As per military assessment, Israel's air force (composed mainly of F15s and F16s)  would have to fly over 1600 km and back, over hostile air space,  refuel in mid flight, fight off anti-air defenses and  which are built in mountains and bomb installations which are built under 30 feet of reinforced concrete. 
Herculean task no doubt, but the Israelis have done it before - in 1981 to Osirak, (Operation Opera) and in 2007, Syria (Operation Orchard).
So it all boils down to whether the US gives the go-ahead to Israel or not.