Do the following electron configurations represent a possible state of an element? If so, (i) identify the element and (ii) determine if this is the ground state or an excited state. If not, why not?

a. \(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2}\)

b. \(1 s^{2} 2 s^{2} 2 p^{7} 3 s\)

c. \(1 s^{2} 2 s^{2} 2 p^{4} 3 s^{2} 3 p^{2}\)