A typical lightning bolt has about 10.0 c of charge. how many excess electrons are in a typical lightning bolt?

The charge of an electron is - 1.602 x 10^-19 Coulombs. If an average lightning bolt carries around 10.0 Coulombs of charge, we can simply divide this by the charge of an electron to estimate the total number of excess electrons:

(10.0 C) / (1.602 x 10^-19 C/electron) = 6.24 x 10^19 electrons

So there are around 6.24 x 10^19 excess electrons in a typical lightning bolt.