What is important about all this is that the social behaviour of atoms – the branch of science known as chemistry -depends largely on how many atoms there are in the outer orbit. It is as if atoms are more comfortable with filled orbits, and are constantly searching for partners to swap electrons and achieve peace. For example, if one atom has seven electrons in its outer circle, it behaves like a collector trying to fill that yawning gap on its shelf and snaps up any electron around.