Question

${{\text{C}}^{{\text{14}}}}$ is:

A.A natural non-radioactive isotope
B.An artificial non-radioactive isotope
C.An artificial radioactive isotope
D.A natural radioactive isotope

Answer 1

${{\text{C}}^{{\text{14}}}}$ is an isotope of carbon. The neutron to proton ratio determines the stability of the nucleus. A stable nucleus has a neutron to proton ratio 1:1. ${{\text{C}}^{{\text{14}}}}$ is used to determine the age of organic material using the carbon-14 dating method.

Step by step answer: The stable nucleus of carbon is ${{\text{C}}^{{\text{12}}}}$ that has atomic mass 12 atomic number 6. Atomic number indicates the number of protons present in the nucleus.

So, the number of protons in ${{\text{C}}^{{\text{14}}}}$ = 6

Atomic mass = number of protons + number of neutrons

Atomic mass of ${{\text{C}}^{{\text{12}}}}$ =12

Number of protons = 6

Thus, number of neutrons = 12-6 = 6

As ${{\text{C}}^{{\text{12}}}}$ contain an equal number of protons and neutrons so neutron to proton ratio is 1:1 and thus ${{\text{C}}^{{\text{12}}}}$ is a stable nucleus.

Similarly, determine the neutron to proton ratio for ${{\text{C}}^{{\text{14}}}}$ nucleus.

${{\text{C}}^{{\text{14}}}}$ is the isotope of ${{\text{C}}^{{\text{12}}}}$ so it will contain the same number of protons as ${{\text{C}}^{{\text{12}}}}$

Atomic mass of ${{\text{C}}^{{\text{14}}}}$ =14

Number of protons = 6

Thus, number of neutrons = 14-6 = 8

As ${{\text{C}}^{{\text{14}}}}$ contain 8 neutrons and 6 protons so neutron to proton ratio is 1.3:1 and thus ${{\text{C}}^{{\text{14}}}}$ is an unstable nucleus. These unstable nuclei always try to achieve stability. To achieve the stability excess neutrons are converted into protons and nuclei are said to be radioactive nuclei.

So, ${{\text{C}}^{{\text{14}}}}$ is a radioactive isotope.

${{\text{C}}^{{\text{14}}}}$ isotope present in a living organism and it is used to determine the age of organic material using the carbon-14 dating method.

Hence, ${{\text{C}}^{{\text{14}}}}$ is a natural radioactive isotope.

Thus, the correct option is (D) a natural radioactive isotope.

Note: The stability of the nucleus mainly depends on the number of protons and neutrons present in it. A neutron to proton ratio of the stable nucleus is always 1:1. Isotopes are the atoms of the same element having the same atomic number but a different mass number. Isotopes always contain the same number of protons but a different number of neutrons.