Question

Why does the group 15 elements called Pnicogens and group 16 elements called Aerogen.

Answer 1

Group 15 elements are called pnicogens because they are poisonous and choking in nature. Pninogen means "to choke".
Group 16 elements are not called 'aerogens' they are called chalcogens because they are ore forming elements.
The noble gases or group 18 elements are called 'aerogens'.