Which of the following pairs of elements could NOT react to form an ionic compound ? Check all that apply Co and Br
C and O
K and F
Ag and O

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.