C involves sound waves not electromagnetic waves (light)
Cr(chromium) is number 24, meaning that it has 24 protons, and 24 electrons. You subtract the atomic number from the atomic mass to get the number of neutrons. 50-24=26 neutrons. There are other isotopes that have more neutrons, as the mass on the periodic table is 52.
See the attached picture.
The sentences have been carefully dragged to the right places.
Answer:
I don't really know
Explanation:
So I'm going to look it up