Question

I have to write a bunch of atomic symbol for these isotopes and I don't understand how to I do it.

(a) atomic number=53, number of neutrons=79

I looked at the periodic table for 53 so the element is Iodine. So They gave the atomic number and I have the element, I need the mass #...

(b) number of protons = 29, mass number = 65

Would the element be Cu (Copper)?

(c) number of protons = 27, number of neutrons =31

element is Co (cobalt) ?
mass number= I don't know how to get that.

Please help me, thank you!

Answer 1

mass number = number of protons + number of neutrons.
b. Yes, Cu is element #29. This isn't difficult. The atomic number is the number of protons, the mass number is number of P + neutrons of n. If you can count from 1 to 116 or so you can look these up on the periodic table.

Answer 2

Thanks! It's been awhile since I took chemistry.