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.

There is one s orbital, and there are three p orbitals, five d orbitals, and seven f orbitals. thus, the answer is b. do not confuse the number of orbitals in a subshell with the number of electrons the subshell can hold. each orbital can hold two electrons, so the capacity of an nf subshell is 14 electrons.