Question

The element chlorine has two naturally occurring isotopes, 35-Cl and 37-Cl.
Which is true about the atomic mass of chlorine provided on a periodic table?

A The atomic mass is calculated using the weighted average of the isotopes.

B The atomic mass is based on the isotopes with the most neutrons.

C The atomic mass for the most abundant isotope is used.

D The atomic mass is based on the number of protons and neutrons in the nucleus.

Answer 1

We take the average. That's why in the periodic table, we see many decimal places for atomic mass.

Answer 2

Thanks, I thought that it was A or C now I know it's A.