(3). Calculate the total number of electrons (E) needed to complete the octet with all the atoms in the molecule or ion by eq.1. In the case of existing hydrogen atoms, two electrons will be added to each of these atoms instead of eight. E = 8e -x M + 2e -x N eq.1 M = the total number of non-hydrogen atoms; N = the total number of hydrogen atoms (4). The number of bonding electrons (shared electrons) is determined by ( ) -(