Question

0.Copper has two naturally occurring isotopes 63Cu and 65Cu. If the average atomic mass of copper is 63.546 u, then natural abundance of lighter isotope of Cu will be [NCERT Pg. 17] (1) 46.4% (2) 27.3% (3) 54.2% (4) 72.7%​

Answer 1

Answer:

Let the natural abundance of  

63  Cu isotope be x%.  

The natural abundance of   65  Cu isotope will be 100−x.  

The average atomic weight is 63.546 g.

Hence, 100×63.546=63x+65(100−x)

6354.6=63x+6500−65x=6500−2x

2x=145.4

x=72.7

Hence, the natural abundance of the  

63  Cu isotope is 72.7%

So, the correct option is D.

Explanation:

Please mark my answer as the brainliest if u like it.

Answer 2

Answer:

answer:: 72.7%

thank you