Answer:
D. nitrogen (n)
Step-by-step explanation:
The periodic table shows all known elements and puts them into groups, also known as families.
Valence Electrons
Valence electrons are electrons found on the outermost energy level. This means that they are farther from the nucleus than other electrons. Valence electrons are the electrons that are involved in both covalent and ionic bonding. Atoms become an ion when they gain or lose valence electrons.
Main Families
All of the elements listed are in a main family. This means they are either from groups 1, 2, 13, 14, 15, 16, 17, or 18. If you look at a periodic table, these are the taller groups. Note that transition metals are not considered to be a main group.
For all elements within main groups, their number of valence electrons can be found through their group number (with the exception of He due to its small size).
Counting Valence Electrons
For groups 1 and 2, the number of valence electrons is equal to the group number. For example, Mg is in group 2 and has 2 valence electrons. Na is in group 1 and has 1 valence electron.
For groups 13-18, the number of valence electrons is equal to the group number minus 10. For example, O is in group 16 and has 6 valence electrons.
Group 15
The rules above tell us that any element in group 15 will have 5 valence electrons. Group 15 is also known as the nitrogen group because it is the first element listed. So, we know that nitrogen is in group 15. This tells us that nitrogen must have 5 valence electrons.