Which of the following represents an isotope for lithium (73Li)? a) 35 LI
b) 3.Li
c) 37Li
d) 43Li

The correct answer is - option b) 3Li .

Explanation:

Lithium that is occurring naturally have two isotopes that are stable one with an atomic mass of 7 and the other with an atomic mass of 6 both have the same atomic number.

In question 7(atomic mass) 3 (atomic number) is given and there is only two option have 3 atomic number with 3 b) 3.Li and d) 43Li. 4 atomic mass is not naturally occurring isotopes and as option b) has a no atomic mass so it would be the correct answer.

Thus, the correct answer is - option b) 3Li .