75 J. All I did was multiply the 2 numbers to get 75
It will be 3 wavelengths because 1 cycle = 1 wavelength.
Answer:
A. Ar, Si, Mg, Na
Explanation:
ar is argon which is an inert gas. its in group 18. whole column is filled with inert gases.
na is sodium. very reactive. its in group 1. whole column is filled with very reactive elements
They are hard to detect because they have no electric charge