Matching Pairs Atomic Structure MatchingOnline version 8.5AB by Courtney Cox 1 cloud 2 charge of neutron 3 charge of electrons 4 Stable Atom 5 nucleus 6 atomic mass = 7 Reactive Atom 8 valence electrons 9 charge proton center of an atom, contains protons and neutrons negative - no charge, 0 area surround the nucleus happy atom! Has a full valence shell (8ve-) protons + neutrons sad atom, doesn't have a full valence shell (less then 8) so it wants to bond with others electrons farthest from the nucleus, responsible for reactivity/bonding positive +