I need to draw dot and cross diagrams to explain how they bond, but if the aluminium outer shell has 13 electrons and the oxygen one has 6, how do they all become happy atoms, and all have a full outer shell? please help! thank you.Aluminum\'s outer shell is 3, not 13. 13 is the total number of electrons it has. Looking a the periodic table, Oxygen\'s usual valance state is -2 as an ion. Aluminum\'s valance state is always +3. This means that oxygen gains 2 electrons to get a charge of -2 and aluminum lose 3 electrons to get a charge of +3. As for electron configuration, aluminum has 13 electrons in total. 2 e- is in the 1st sublevel. 8 e- is in the 2nd sublevel. That leaves 3 e- left but 3 is not a stable number so aluminum wants to lose those 3 e- to become stable. Oxygen has 8 electrons. 2 e- is in 1st. 6 e- is in 2nd. 6 is not a stable number so oxygen wants to gain 2 more e- to become a full set of 8. Aluminum want to lose 3, Oxygen want to gain 2. We need to balance those. 3 x 2 = 6 2 x 3 = 6 Because Aluminum\'s usual state is +3, we can have 2 Aluminum atoms bonding. If both lose 3 e-, they both have stable outer shell of 8 (2nd sublevel) and lose 6 e- in total. Oxygen\'s usual state is -2, but there are 6 e- to gain to oxygen can have 3 atoms bonding. If all 3 atoms receive 2 e- in each, then that\'s 6 and they\'re all stable, also at 8 e-. So in order to turn them into happy atom, we need 2 Aluminum and 3 Oxygen to bond together. So the chemical formula is Al2O3 (Aluminum Oxide) *** I\'m not very good at explaining, I did the best I can. As for the drawing, I can\'t do that on the computer. It would have been a whole lot easier if I can though.Aluminium Oxide Ionic BondingI really do not know so ask somebody elseOther related question