Final answer:
Nitrogen has two electron shells, and its valence shell contains five valence electrons, making option (d) five the correct answer.
Step-by-step explanation:
Nitrogen (N) is an element with an atomic number of seven, which means it has seven electrons. When considering the distribution of electrons in shells, these seven electrons will fill the first shell, which can only hold two electrons, and the remaining five will fill the second shell since the first shell's capacity is already full. Hence, nitrogen has two electron shells.
Regarding the number of valence electrons, these are the electrons in the outermost shell of an atom that are involved in chemical bonding. For nitrogen, the five electrons in its second shell are its valence electrons. Therefore, nitrogen has a total of five valence electrons, making the correct answer to the question (d) five.