The element copper has naturally occurring isotopes with mass numbers of 63 and 65. The relative abundance atomic masses are 69.2% for mass=62.9 amu, and 30.8% for mass= 64.93 amu. Calculate the average atomic mass of cooper.

The relative atomic mass of copper here, is the weighted average of each isotope.

For example, Take Bromine. There are two isotopes of Bromine, namely Br-79 and Br-81, each being of 50% abundance.

The relative atomic mass of bromine is therefore given by:

(79 \times 50%) + (81 \times 50%) = 80

Can you try this for copper now?

Describe the relationship between atomic radii and atomic number for the group A elements in the first four periods.

If you can answer this thank you!