Question

Why are the group $15$ are known as pnictogens?

Answer 1

The set of arrangements of all the atoms in accordance to their various properties is known as the periodic table. Today the periodic table which we see is a long form of the periodic table given by Henry Moseley in the year of $1913$ . The earliest known periodic table was developed by Johann Wolfgang Dobereiner in the year of $1817$.

Complete answer:
In the early $1800's$ all the scientists were working on the arrangement of all the known elements in an ordered form. The earliest known such arrangement was given by Johann Wolfgang Dobereiner in the year of $1817$ . Then in $1862$ De chancourtois tried to arrange the elements. In $1865$ Newland presented his periodic table. The main limitation of all the above tables was that they were limited to few elements only or were too complicated to be understood by anybody.
In $1869$ Lother meyer and D. Mendeleev overcome the above limitations by arranging all the known elements in the simplest manner and leaving space for new elements which were not discovered yet. Their table was based on the function of atomic weight. However they failed to explain the anomalous behavior of different elements, and many more.
In $1913$ Henry Moseley arranged all the known elements as the function of atomic number. According to this law the table has $7$ periods and $18$ groups.
Group $15$ are known as pictogens because in Greek language pigeon stands for chalk. In absence of oxygen, this group has properties to cholk.

Note:
Group $1$ is known as alkali metals, group $2$ is known as alkali earth metals, group $13$ is known as icosagens, group $14$ is known as crystallogens, group $15$ is known as pnictogens, group $16$ is known as chalcogens, group $17$ is known as halogens, and group $18$ is known as the noble gases. Group $15$ includes the nitrogen family.