Can electrons be present outside orbitals. If yes how does this affect chemical reactions
There are more levels of abstraction involved. At first, orbitals are simplification and they are best described as "one electron wavefunction", ie. area of space where one electron can reside (or two, if you think of spatial orbitals, as opposed to spin-orbitals). 

Being expressed as a wavefunction, the orbital (and therefore electron residing in it) has nonzero probability in whole space (I mean, whole universe). But the probability decays very fast. 

If you plot a probability density, see image below, you can clearly see the behaviour. If, on the other hand, want to plot the 3d surface, which are often shown in textbooks, you have to state some cutoff value. Often it is probability density of 0.9, ie. 90%. By this you obtain the typical pictures of orbitals.



I would deliberately leave your question without answer, as they stem from severe confusion caused by your textbook.