When an atom's outer electron shell is only partially filled, the atom is considered?

The Atom it considered Chemically Unstable

It would be considered atomically unstable because it wants to gain or loose electrons so that it will be like the noble gases. It will steal or give away electrons to other atoms.

So what you would do is go through and add 3 teaspoons(tsp) 6 times because of the 6 tablespoons(tbsp). which will give you an answer of 18. another way is to multiply 3x6=18.