Which of the following is a group 15 element? (A) Na, (B) N, (C) Ni, (D) Ne, (E) Nb.
In order to determine which of these elements are located in group 15, let us identify the location of each element within the periodic table and also identify a group within the periodic table. A group of elements are located vertically within the periodic table, whereas a period is located horizontally. There are 18 groups within the periodic table numbered one through 18.
Let us begin with option choice (A) Na, sodium, which is located in group one and is an alkali metal. Since Na is in group one, not 15, option choice (A) Na is not the correct answer choice.
Now, let us move on to option (E) Nb, niobium, which is a transition metal located in group five. Since Nb is in group five, not 15, option choice (E) Nb is not the correct answer choice.
The next element within the periodic table is option (C) Ni, nickel. Nickel is also a transition metal but is located in group 10. Since Ni is in group 10, not 15, option choice (C) Ni is not the correct answer choice.
Option choice (D) Ne, neon, is located in group 18 and is classified as a noble gas. Since Ne is in group 18, not 15, option choice (D) Ne is not the correct answer choice.
Now, let us look at option (B) N, nitrogen, which is located in group 15 along with phosphorus, arsenic, antimony, bismuth, and moscovium. Therefore, option choice (B) N, nitrogen, is the correct answer choice, since it is the only element in group 15.