Isotopes and Atomic Mass…

1. The average atomic mass for carbon is 12.011. There are two naturally occurring carbon isotopes, ¹²C and ¹⁴C. Which do you think is more abundant in nature? Explain your reasoning.

2. The two naturally occurring isotopes of boron are ¹¹B and ¹⁰B.

a. Determine the number of neutrons in each isotope.

b. In nature 80.1% of the naturally occurring boron is ¹¹B, while 19.9% is ¹⁰B. Show your calculations to determine the average atomic mass of boron. Assume the mass of a proton = mass of a neutron = 1.00 amu

3. There are two naturally occurring isotopes of lithium. One has 6 neutrons, while the other has 7 neutrons.

a. Calculate the mass number of each isotope of lithium.

b. Of all the naturally occurring lithium, 92.5 % has 7 neutrons. The remainder has 6 neutrons. Show your calculations to determine the atomic mass of lithium.

Assume the mass of a proton = mass of a neutron = 1.000 amu

4. The atomic mass of chlorine is 35.453 amu. The abundance of ³⁵Cl is 75.77%. Assuming there are only two natural isotopes, what is the abundance of ³⁷Cl? Does the data support your assumption of two isotopes?