Nuclei – Solutions
1) Two stable isotopes of lithium, 63Li and 73Li, have respective abundances of 7.5% and 92.5%. These isotopes have masses 6.01512 u and 7.01600 u, respectively. Find the atomic mass of lithium.
(a) According to the question:
Mass of lithium isotope 63Li, m1 = 6.01512 u
Mass of lithium isotope 73Li, m2 = 7.01600 u
Abundance of 63Li, ƞ1 =7.5%
Abundance of 73Li, ƞ2 = 92.5%
The atomic mass of lithium atom is given as: