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xing2009

define the term nucleon number(mass number) of an isotope。

xing2009

回复 2# C.YYang


    这些我都懂～我是要我上面的问题的答案哦～

C.YYang

nucleon number- number of protons and neutrons present in an atom
isotope - a same element with the same number of protons but have different neutron number
nucleon number of an isotope may vary even though it is the same element because of its different number of neutrons in it, such as carbon-12 and carbon-13.