Question

Carbon has two naturally occurring stable isotopes, carbon-12 (12C) and carbon-13 (13C). Of all the carbon on Earth, 98.93% is carbon-12 and 1.07% is carbon-13. How many neutrons are in each isotope of carbon?

Answer 1

Carbon-12 (12C) has 6 neutrons, and carbon-13 (13C) has 7 neutrons. This is calculated by subtracting the number of protons (6) from the isotopes' mass numbers (12 for 12C and 13 for 13C).

Step-by-step explanation:

Carbon has two naturally occurring stable isotopes: carbon-12 (12C) and carbon-13 (13C). The isotope carbon-12 has a mass number of 12, which includes 6 protons and 6 neutrons, giving it 6 neutrons. Carbon-13, however, has a mass number of 13, which means it has the same number of protons but one additional neutron, totaling 7 neutrons. Knowing the atomic number of carbon is 6, which is the number of protons in the nucleus, a simple subtraction of the atomic number from the mass number (12 or 13) will give us the number of neutrons in each isotope, 6 and 7, respectively.

While carbon also has a radioactive isotope, carbon-14 (14C), with 8 neutrons, it is not considered stable and is present only in trace amounts; thus, it does not significantly factor into the abundance percentages of carbon isotopes on Earth.