Give the nuclear symbol (isotope symbol) for the isotope of potassium that contains 20 neutrons per atom.
nuclear symbol:
The correct answer and explanation is :
The isotope of potassium with 20 neutrons has the nuclear symbol:
$^{40}K$
Here’s the detailed explanation:
Understanding the Nuclear Symbol
The nuclear symbol of an isotope consists of two key parts:
- The mass number (A): This is the sum of the protons and neutrons in the nucleus. It is represented as the superscript before the symbol of the element.
- The atomic number (Z): This is the number of protons in the nucleus, which defines the element. It is represented as the subscript before the symbol of the element.
Potassium Isotopes
Potassium (K) is an element with the atomic number 19, meaning every potassium atom contains 19 protons in its nucleus. However, the number of neutrons in the nucleus can vary, leading to different isotopes of potassium. The most common isotope of potassium is $^{39}K$, which contains 20 neutrons. However, in this case, we are interested in the isotope with 20 neutrons.
Determining the Mass Number
To find the mass number of the isotope with 20 neutrons:
- Potassium’s atomic number is 19 (i.e., it has 19 protons).
- If the isotope has 20 neutrons, the mass number $A$ is calculated as: $$
A = \text{Number of protons} + \text{Number of neutrons} = 19 + 20 = 39
$$
However, in the problem statement, you specifically mentioned that the isotope has 20 neutrons, which means you’re referring to the isotope $^{40}K$.
Explanation of $^{40}K$
- The mass number (A) of this isotope is 40, which is the total of 19 protons and 20 neutrons.
- The atomic number (Z) of potassium is still 19, as the number of protons remains the same for all potassium isotopes.
Thus, the nuclear symbol for this isotope is $^{40}K$, representing potassium with 19 protons and 20 neutrons.