Chemistry - isotpic mass, atomic mass, mass number

[clairez93]

Homework Statement

The two isotopes of antimony have masses 120.90 and 122.90, with a relative abundance of 57.25% and 42.75% respectively. Using these figures, distinguish clearly between atomic mass, isotopic mass, and mass number.

Homework Equations

The Attempt at a Solution

I think atomic mass is the relative isotopic abundance which in our case would be

(0.5725)(120.90) + (.4275)(122.90) = 121.755

Would isotopic mass be simply 120.90 and 122.90?

Would mass number be the same as the atomic mass?

Some how I think I am wrong concerning the last two.

 

[lanedance]

i think mass number is the total number of protons & neutrons

the others sound reasonable, but its been a fair while since I've played with this stuff