write isotpoic symbols of the form X-A (for example, C-13) for each of the following isotopes.

**Do I add the number of protons and neutrons together to get the answer?
The symbol is easy to figure out.**

a) the iodine isotope with 74 neutrons

B) the phosphororus isotope with 16 neutrons

C) the uraanium isotope with 234 neutrons

D) the argon isotope with 22 neutrons

Yes. The symbol is the atomic number as well as the number of protons.
# protons + # neutrons = mass number.
I-(53+74)= I-127

I wasn't sure about this one. I thought the number that I got was too big. But you showed me I did it right thanks!

Ha! I forgot to change my brothers name from the box.

But yeah that was melinda. Thanks!

I wonder if the U one is correct. There is a U-234 but there is no U-(92+234)=U-326.