electrons

electrons

1. number of protons determines place in periodic table

   • number of electrons is same as number of neutrons

2. arranged in shells at different distances around the nucleus

   • proton number increases by one for each element

3. number of electrons in outer shell determines the group theyre in

   • group zero is an exception because it comes after seven, usually having 8 electrons in the outer shell, except helium which has 2
     • period number = how many shells there are, group number - how many electrons in outer shell