Which of the following would be an isotope of ^14N?
The Correct Answer and Explanation is:
The correct answer is:
^15N
Explanation:
To understand why ^15N is an isotope of ^14N, we need to review what isotopes are and how they are defined. Isotopes are variants of the same chemical element that have the same number of protons but different numbers of neutrons. Since the number of protons determines the element, all isotopes of an element have the same atomic number (Z) but differ in their atomic mass (A) due to the variation in neutrons.
- Identifying Characteristics of Nitrogen:
- Nitrogen has an atomic number of 7, meaning it always has 7 protons.
- The atomic mass of nitrogen isotopes, however, can vary depending on the number of neutrons in each atom’s nucleus.
- ^14N and ^15N:
- ^14N has an atomic mass of 14, meaning it has 7 neutrons (14 – 7 = 7).
- ^15N, on the other hand, has an atomic mass of 15, which means it has 8 neutrons (15 – 7 = 8).
- Both ^14N and ^15N have 7 protons, fulfilling the requirement to be forms of nitrogen, but they differ in neutron count.
- Why ^15N Is an Isotope of ^14N:
- Because isotopes are defined by the same atomic number but different mass numbers, ^15N is an isotope of ^14N. The increase from 7 to 8 neutrons doesn’t change the element’s identity but creates a different isotope.
- Other elements with a different atomic number, like ^15O or ^13C, would not be isotopes of nitrogen because they have different numbers of protons.
- Uses and Stability:
- ^14N is the most abundant nitrogen isotope, making up about 99.6% of natural nitrogen. ^15N, though less common, is stable and used in scientific applications such as tracing nitrogen movement in ecosystems due to its unique neutron count.
Thus, ^15N is an isotope of ^14N due to having the same atomic number (7 protons) but a different mass number (8 neutrons in ^15N compared to 7 in ^14N).