Answers:
The average atomic mass will be closer to 7 amu, the average atomic mass of lithium is 6.94 amu and it is the same as the atomic mass on the periodic table.
Explanations:
We can predict that the average atomic mass will be closer to 7 amu because Li-7 has a much higher abundance on earth than Li-6.
To get the average atomic mass using isotopes, we must multiply the mass of each isotope by its natural abundance and then add the products.
(6.0151223 × 0.075) + (7.0160041 × 0.925)
= 0.45 + 6.49
= 6.94 amu
Our calculated average atomic mass is the same as the atomic mass on the periodic table.