The truth: the above is a good model for understanding most of basic chemistry but in reality electrons aren't remotely like planets orbiting the sun. Electrons move so fast that basically one moment they'll be in one place and the next they'll be in a totally different place (although it is more likely to be in a certain place). Therefore a single electron effectively forms a 'cloud' around the nucleus, a cloud of dispersed negative charge, which is densest around where it is traditionally seen as having an orbit.