Answer:
different number of isotopes
Explanation:
Chlorine has isotopes which are different even though they apply to the same element. Chlorine has the isotopes 35 and 37, in a 3:1 arrangement and the average of the isotopes is about 35.5(you do not round the decimal)
to calculate relative atomic mass of chlorine-35 and chlorine 37:
(occurance in nature/100)*35+ (occurance in nature/100)*37=35.5
occurance in nature for chlorine 35: 75%
Ocurance in nature for chlorine 37: 25%
so
75/100*35= 26.25
26.25 +(25/100)*37=35.5
26.25+9.25=25.5
Hope this helps!
