Final answer:
The total valence electrons in NCl3 is 26, which is found by adding the 5 valence electrons from nitrogen to the 21 valence electrons from the three chlorine atoms (7 each). Option b is correct.
Step-by-step explanation:
The total number of valence electrons in NCl3 is calculated by adding the valence electrons of nitrogen and the valence electrons of each chlorine atom. Nitrogen, which is in group 15 of the periodic table, has 5 valence electrons. Chlorine, found in group 17, has 7 valence electrons.
Since there are three chlorine atoms in NCl3, we multiply the number of valence electrons of chlorine by 3. The calculation is as follows: Nitrogen valence electrons (5) + Chlorine valence electrons (7) × 3 chlorine atoms = 5 + (7 × 3) = 5 + 21 = 26 valence electrons. Therefore, the correct answer is 26 valence electrons for NCl3.