I, in general, have an inclination to perceive the relations of atoms like the relations of humans
The elements at leftmost column of the periodic table have something ready to share in hand, one electron, but they are alone
.. and the elements at rightmost side of the periodic table (the ones right before the "completed elements", the noble gases) the will be complete with someone, and in need of that one electron to be complete.. whenever they see each other, they say thats!.. and they feel completed with each other
Many things in chemistry is acting like humans
PS: With "rightmost elements" I dont mean the noble gas elements, I mean halogens.. the actual rightmost ones are noble gases, but they are so complete that we dont see them active.. so I put them aside as "complete elements".