(a) give the formula of the chromium-contaning species in solution X

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.

The formula is (nh4)2co3

Both models are effective because they show the valence electrons, and these valence electrons indicate the reactivity of an element.