Final answer:
Nitrogen, with an atomic number of seven, has seven electrons. These electrons fill up two electron shells: two in the first shell and five in the second. Hence, the correct answer is option b. two.
Step-by-step explanation:
When considering nitrogen and its place on the periodic table, we can see that it has an atomic number of seven. This number represents the total amount of protons in the nucleus of a nitrogen atom and, by extension, also indicates the number of electrons the atom has when it is neutral. Electrons are organized around the nucleus in different layers known as electron shells. The arrangement of electrons into shells follows a specific order, where the first shell can hold up to two electrons and the second can hold up to eight.
For nitrogen, with its seven electrons, the first two will occupy the first shell, and the remaining five will be in the second shell. This means nitrogen will have two electron shells to accommodate its electrons. Therefore, the correct answer to the question is option b. two.