The nineteenth-century emigration of a large number of Swedes from a particular region of Sweden to Isanti County, Minnesota, as a result of communications from friends and relatives who preceded them there is an example of

because the two particles have an equal charge, the charges will cancel out and give the atom an overall charge of 0. so, if at atom has 35 protons in the nucleus, we could expect it to have 35 electrons orbiting that nucleus.