Do you know?

I had a very interesting discussion with a 6 year old yesterday.
I started on a new topic this week - The Human Body.
There was a model of the human body and I started with disassembling and
assembling the organs.
After the exercise some of the kids decided to play with other stuff and this guy came to me and
said : Do you know that the human body is made up of molecules?
I : Yeah, I do know
He : Do you know what molecules are made up of?
I : Yeah atoms
He : Do you know what atoms are made up of?
I : Yes, electrons, protons and a nucleus
He : Do you know what the nucleus is made up of?
I : Yes, neutrons and protons
Now he was going too deep into this theory and I was getting worried.. :)
He wasnt too happy that I gave him the answers till now so he then went on
He : Do you know why atoms combine to form molecules?
I : Because they get attracted to each other.
He (Was finally very happy) : No! Its because they dont have enough electrons in their outer shell!
I (Stunned) : Okay! Yeah you are right.
Then he went on to explain why some elements dont combine while some do. He said two oxygen atoms combine to make the oxygen molecule and this molecule combines with hydrogen to make one water molecule.
I was really glad. He knew the stuff not just by-hearted but he actually could understand the concept.
He also told me that electrons when they move out of the their shell, they create holes and since electrons keep moving out of their shells, atoms and hence molecules have holes and hence we humans are made up of primarily holes!!!!
I didnt know what to say!
But I cant deny I had fun. It was a challenging day!